Need help with my geometry

[Egon]

LD1, I just posted a fairly easy question (that I didn't know the answer to) without complete details of angles, exact lengths, etc. because I just needed to know how much concrete to order and I always order at least 1/2 a yard extra so I didn't need an exact answer and I did not supply exact details because I did not think it would really matter. Most people would assume that the top and bottom lines were parallel from my original drawing and give me a close enough answer for my question, which they did.

Now you say you did not answer earlier because you did not want to assume that the lines were parallel until I revealed that it was for a driveway apron and then you "assumed" that they were parallel.

Well, so much for assuming. They actually are not parallel and the 2 sides are different lengths though I did not disclose this earlier because I did not want to over-complicate the matter and I had another part also that was a rectangle of 8' X 10' that I was easily able to figure was 80 sq. ft. that I added on to your correct answers without disclosing.

Now if any of you wish to tell me the exact measurement of my apron from the enclosed drawing, with more details, and the amount of concrete I should order, adding 1/2 yard extra, to be safe, please do so. I will see how much it varies from the 10 1/2 yards I am planning to order.

PS: The concrete is 6" thick.

View attachment 465773

Did you want that with twelve place log tables?

 

[LD1]

it's time to go back to school for me! My last calculation was wrong! The unknown leg in the triangle is 22'.the area of the figure is 440 sqft. Sorry about that!

:thumbsup:

 

[zzvyb6]

You all have forgotten to subtract the area of the form boards and also the area of the crack and joint sections as well as the volune of the rebar placed within. That amount can get you some extra thickness.

 

[SPYDERLK]

You all have forgotten to subtract the area of the form boards and also the area of the crack and joint sections as well as the volune of the rebar placed within. That amount can get you some extra thickness.

u got it on the couple cuft of rebar. Might want to raise the 2nd course a thou or two. -- Maybe no crack focuses. -- Forms are on the outside.

 

[tallyho8]

Did you want that with twelve place log tables?

I didn't know what a 12 place log table was so I Googled it.

But I'm not sure what that has to do with concrete.



:laughing:

 

[ovrszd]

I didn't know what a 12 place log table was so I Googled it.

But I'm not sure what that has to do with concrete.

View attachment 465826

:laughing:

Good one!!! I thought it was some mathematical tble that I knew nothing about, as usual.

 

[Egon]

I didn't know what a 12 place log table was so I Googled it.

But I'm not sure what that has to do with concrete.

View attachment 465826

:laughing:

The twelve place log tables allow you to do a very precise calculation of the area!

 

[k0ua]

The twelve place log tables allow you to do a very precise calculation of the area!

We all used log tables until calculators were common

 

[2LaneCruzer]

Aw, heck. All you need is an analytical scale and some high grade paper. Draw any figure, say a square to scale, cut it out and weigh it. Draw your unknown to scale, cut it out and weigh it. Ratio it, using milligrams/sq. ft. as calculated from your known figure. Done and done.

 

[Egon]

We all used log tables until calculators were common

Great fun they were to use to. Interpolation used to be one of least enjoyable practices.