# Anyone up on geometry? I need an angle.

Joined: February 27th, 2005, 8:37 pm
Hello:

I am embarrassed to say I forgot how to solve a simple geometry problem even though geometry was my strongest math way back in 10th grade, and I have an engineering degree from a "previous life." I guess if you don't use it, you lose it.

I am going to taper legs for a sofa table I am making for friends who lost their home in a fire. I have been making replacement furniture for them. It's an excuse to do some woodworking since model kits are so expensive now. Plus, I'm getting far-sighted.

Basically, the taper forms a triangular piece of scrap wood from a 27.25" long piece. The taper begins 5" down and a triangular scrap piece will be 22.25" long (side "a") x 1/2" wide (side "b"). I have "a" and "b" sides of a square triangle. A square corner being formed by "a" and "b" at the bottom. I am not worried about the hypotenuse's ("c") length. The cut will leave a 1" wide foot with the original width being 1.5".

What I want is the angle formed by this scrap piece's vertex opposite side "b" so I can set a table saw tapering fence properly.

Am I correct in thinking I can get this angle by using the tangent of b/a? Actually, I think the arc-tangent would give an angle. Since I don't know the hypotenuse's length, but I have two sides, tangent is the function to use?

I do realize, however, the pythagorean theorem would let me calculate side "c." That would then allow the use of either sine or cosine.

Just wondering. I don't want to mess up a lot of wood doing trial and error cuts. I am pretty sure of myself, but I thought I'd share this problem with you guys.

Thanks.

- Dustin Faulkner

Joined: February 27th, 2005, 3:08 pm

It looks like about a 1 and a half degree angle

or more closely if you use InvTan about 1.28 degrees but getting .28 degrees may be tough so I fudged it to 1.5 deg......

Last edited by jbrundt on January 4th, 2012, 8:05 pm, edited 1 time in total.

Joined: June 11th, 2011, 9:54 pm
n/t.

Joined: January 26th, 2006, 10:38 pm
Hello:

I am embarrassed to say I forgot how to solve a simple geometry problem even though geometry was my strongest math way back in 10th grade, and I have an engineering degree from a "previous life." I guess if you don't use it, you lose it.

I am going to taper legs for a sofa table I am making for friends who lost their home in a fire. I have been making replacement furniture for them. It's an excuse to do some woodworking since model kits are so expensive now. Plus, I'm getting far-sighted.

Basically, the taper forms a triangular piece of scrap wood from a 27.25" long piece. The taper begins 5" down and a triangular scrap piece will be 22.25" long (side "a") x 1/2" wide (side "b"). I have "a" and "b" sides of a square triangle. A square corner being formed by "a" and "b" at the bottom. I am not worried about the hypotenuse's ("c") length. The cut will leave a 1" wide foot with the original width being 1.5".

What I want is the angle formed by this scrap piece's vertex opposite side "b" so I can set a table saw tapering fence properly.

Am I correct in thinking I can get this angle by using the tangent of b/a? Actually, I think the arc-tangent would give an angle. Since I don't know the hypotenuse's length, but I have two sides, tangent is the function to use?

I do realize, however, the pythagorean theorem would let me calculate side "c." That would then allow the use of either sine or cosine.

Just wondering. I don't want to mess up a lot of wood doing trial and error cuts. I am pretty sure of myself, but I thought I'd share this problem with you guys.

Thanks.

- Dustin Faulkner
Hypoten who???? Tangent... I go off on them sometimes!

Hahhahaaaa, man am I glad I don't have to do that stuff anymore!

We stole the eagle from the Air Force, the anchor from the Navy, and the rope from the Army.
On the seventh day while God rested, we overran his perimeter, stole the globe, and we've been running the whole show ever since.

Semper Fi, Don
“Some people spend an entire lifetime wondering if they made a difference in the world. But, the Marines don't have that problem.”
- Ronald Reagan

Semper Fi, Don
Luke: 22:36

Joined: February 27th, 2006, 6:25 pm
Hello:

I am embarrassed to say I forgot how to solve a simple geometry problem even though geometry was my strongest math way back in 10th grade, and I have an engineering degree from a "previous life." I guess if you don't use it, you lose it.

I am going to taper legs for a sofa table I am making for friends who lost their home in a fire. I have been making replacement furniture for them. It's an excuse to do some woodworking since model kits are so expensive now. Plus, I'm getting far-sighted.

Basically, the taper forms a triangular piece of scrap wood from a 27.25" long piece. The taper begins 5" down and a triangular scrap piece will be 22.25" long (side "a") x 1/2" wide (side "b"). I have "a" and "b" sides of a square triangle. A square corner being formed by "a" and "b" at the bottom. I am not worried about the hypotenuse's ("c") length. The cut will leave a 1" wide foot with the original width being 1.5".

What I want is the angle formed by this scrap piece's vertex opposite side "b" so I can set a table saw tapering fence properly.

Am I correct in thinking I can get this angle by using the tangent of b/a? Actually, I think the arc-tangent would give an angle. Since I don't know the hypotenuse's length, but I have two sides, tangent is the function to use?

I do realize, however, the pythagorean theorem would let me calculate side "c." That would then allow the use of either sine or cosine.

Just wondering. I don't want to mess up a lot of wood doing trial and error cuts. I am pretty sure of myself, but I thought I'd share this problem with you guys.

Thanks.

- Dustin Faulkner

Joined: June 11th, 2011, 9:54 pm
Hello:

I am embarrassed to say I forgot how to solve a simple geometry problem even though geometry was my strongest math way back in 10th grade, and I have an engineering degree from a "previous life." I guess if you don't use it, you lose it.

I am going to taper legs for a sofa table I am making for friends who lost their home in a fire. I have been making replacement furniture for them. It's an excuse to do some woodworking since model kits are so expensive now. Plus, I'm getting far-sighted.

Basically, the taper forms a triangular piece of scrap wood from a 27.25" long piece. The taper begins 5" down and a triangular scrap piece will be 22.25" long (side "a") x 1/2" wide (side "b"). I have "a" and "b" sides of a square triangle. A square corner being formed by "a" and "b" at the bottom. I am not worried about the hypotenuse's ("c") length. The cut will leave a 1" wide foot with the original width being 1.5".

What I want is the angle formed by this scrap piece's vertex opposite side "b" so I can set a table saw tapering fence properly.

Am I correct in thinking I can get this angle by using the tangent of b/a? Actually, I think the arc-tangent would give an angle. Since I don't know the hypotenuse's length, but I have two sides, tangent is the function to use?

I do realize, however, the pythagorean theorem would let me calculate side "c." That would then allow the use of either sine or cosine.

Just wondering. I don't want to mess up a lot of wood doing trial and error cuts. I am pretty sure of myself, but I thought I'd share this problem with you guys.

Thanks.

- Dustin Faulkner
The Texas Instrument TI-50 took all the work out of Field Artillery Survey, back in the day. I haven't looked at a book of trig functions or log tables since. Larry(Retired Cannoncocker).
Last edited by CSMO on January 5th, 2012, 5:54 am, edited 1 time in total.

Joined: February 28th, 2005, 5:19 am
Hello:

I am embarrassed to say I forgot how to solve a simple geometry problem even though geometry was my strongest math way back in 10th grade, and I have an engineering degree from a "previous life." I guess if you don't use it, you lose it.

I am going to taper legs for a sofa table I am making for friends who lost their home in a fire. I have been making replacement furniture for them. It's an excuse to do some woodworking since model kits are so expensive now. Plus, I'm getting far-sighted.

Basically, the taper forms a triangular piece of scrap wood from a 27.25" long piece. The taper begins 5" down and a triangular scrap piece will be 22.25" long (side "a") x 1/2" wide (side "b"). I have "a" and "b" sides of a square triangle. A square corner being formed by "a" and "b" at the bottom. I am not worried about the hypotenuse's ("c") length. The cut will leave a 1" wide foot with the original width being 1.5".

What I want is the angle formed by this scrap piece's vertex opposite side "b" so I can set a table saw tapering fence properly.

Am I correct in thinking I can get this angle by using the tangent of b/a? Actually, I think the arc-tangent would give an angle. Since I don't know the hypotenuse's length, but I have two sides, tangent is the function to use?

I do realize, however, the pythagorean theorem would let me calculate side "c." That would then allow the use of either sine or cosine.

Just wondering. I don't want to mess up a lot of wood doing trial and error cuts. I am pretty sure of myself, but I thought I'd share this problem with you guys.

Thanks.

- Dustin Faulkner
of course, looking around my place that's painfully obvious...

Joined: February 27th, 2005, 8:37 pm
Hello:

I am embarrassed to say I forgot how to solve a simple geometry problem even though geometry was my strongest math way back in 10th grade, and I have an engineering degree from a "previous life." I guess if you don't use it, you lose it.

I am going to taper legs for a sofa table I am making for friends who lost their home in a fire. I have been making replacement furniture for them. It's an excuse to do some woodworking since model kits are so expensive now. Plus, I'm getting far-sighted.

Basically, the taper forms a triangular piece of scrap wood from a 27.25" long piece. The taper begins 5" down and a triangular scrap piece will be 22.25" long (side "a") x 1/2" wide (side "b"). I have "a" and "b" sides of a square triangle. A square corner being formed by "a" and "b" at the bottom. I am not worried about the hypotenuse's ("c") length. The cut will leave a 1" wide foot with the original width being 1.5".

What I want is the angle formed by this scrap piece's vertex opposite side "b" so I can set a table saw tapering fence properly.

Am I correct in thinking I can get this angle by using the tangent of b/a? Actually, I think the arc-tangent would give an angle. Since I don't know the hypotenuse's length, but I have two sides, tangent is the function to use?

I do realize, however, the pythagorean theorem would let me calculate side "c." That would then allow the use of either sine or cosine.

Just wondering. I don't want to mess up a lot of wood doing trial and error cuts. I am pretty sure of myself, but I thought I'd share this problem with you guys.

Thanks.

- Dustin Faulkner
I guess I still have a brain despite having been through the college grinder.

I basically did what Jeff did:

0.5"/22.25" (tangent = opposite over adjacent) gives you a number like 0.02247191.

arc tangent of this is 1.287 degrees.

The funny thing is I was proud to be thinking the right thing, but forgot how to use my calculator to do it!

Anyway ... I'll look for 1 - 1.5 degrees on my taper gauge's compass and eyeball 1.25 degrees in the middle. Perhaps just a hair over will be 1.28 - 1.30 degrees.

Man .... how did you guys do it with slide rules?!

- Dustin

Joined: February 27th, 2005, 8:37 pm
Hello:

I am embarrassed to say I forgot how to solve a simple geometry problem even though geometry was my strongest math way back in 10th grade, and I have an engineering degree from a "previous life." I guess if you don't use it, you lose it.

I am going to taper legs for a sofa table I am making for friends who lost their home in a fire. I have been making replacement furniture for them. It's an excuse to do some woodworking since model kits are so expensive now. Plus, I'm getting far-sighted.

Basically, the taper forms a triangular piece of scrap wood from a 27.25" long piece. The taper begins 5" down and a triangular scrap piece will be 22.25" long (side "a") x 1/2" wide (side "b"). I have "a" and "b" sides of a square triangle. A square corner being formed by "a" and "b" at the bottom. I am not worried about the hypotenuse's ("c") length. The cut will leave a 1" wide foot with the original width being 1.5".

What I want is the angle formed by this scrap piece's vertex opposite side "b" so I can set a table saw tapering fence properly.

Am I correct in thinking I can get this angle by using the tangent of b/a? Actually, I think the arc-tangent would give an angle. Since I don't know the hypotenuse's length, but I have two sides, tangent is the function to use?

I do realize, however, the pythagorean theorem would let me calculate side "c." That would then allow the use of either sine or cosine.

Just wondering. I don't want to mess up a lot of wood doing trial and error cuts. I am pretty sure of myself, but I thought I'd share this problem with you guys.

Thanks.

- Dustin Faulkner
n/t

Joined: November 27th, 2004, 5:26 am
What ?
I'd also like to what they are exactly.
Can you get them solar-powered ?