# alright geometry guys

Discussion in 'Hardscaping' started by Dirt Digger2, Mar 28, 2010.

1. ### Dirt Digger2LawnSite Silver Memberfrom PAPosts: 2,396

i couldn't find the hardscaping section...i thought one was in here or i didn't look hard enough

anyway...i am going to be pouring a pond for a fountain. The pond has a 2.5' radius and i will be pouring the concrete 3" thick so the inside of the pond will be 2.25'. I want a 3" overhang with a cut flagstone, so that will take the inside of the flagstone to 2' radius, the flagstone will be 12"x12" so the outside radius of the flagstone will be 3'.

my question is, with a circumference on the outside of 28' (meaning i need 28 stones) at what angle should i be cutting off both sides of the stone to get a wedge shape that is uniform around....

heres a few pictures to help visualize

thank guys

2. ### cetLawnSite Memberfrom TorontoPosts: 89

The circle is 360 degrees. You have 28 pieces so that is 56 cuts. 360 divided by 56=6.4285714.

That's my guess.

3. ### gomowdigLawnSite Memberfrom CaliforniaPosts: 40

First of all DirtDigger2, you might find someone with a degree in CE from Penn State....
But since I always got a real kick out of your farming and dirt moving, I'll give it a shot.

The outer circle of the pavers will have a diameter of 28/3.14 = 8.917 '; the inner circle of the pavers will be approximately 6.917 ' and have a circumference of 3.14 x 6.917 =21.719 '. Dividing by 28 pavers, you have to cut back to 0.776 ' for each paver. You will take off 1.000 - 0.776 =0.3243 ' Now divide by 2 for each side and you have the tangent of the angle = 0.1622 or 9 deg 13 min. I would just mark 0.1622 x 12 or about 1.95 in , make your cut line and saw away. Check my numbers; good luck.

4. ### Dirt Digger2LawnSite Silver Memberfrom PAPosts: 2,396

your right...i was sitting here thinking about it earlier and was having brain farts...but i got up and took a shower and figured it out on the steamy glass door with my finger haha...always have my best thinking time in the bathroom...anyway i will post pictures of the progress

5. ### doubleedgeLawnSite Senior Memberfrom NDPosts: 912

I found that 19 stones that are 12" by 12" would work best:

The outside radius is 36" at it's widest point; the inside radius is 24" at it's widest point.

I used a free program called Google SketchUp to create it. It doesn't make mathematical miscalculations.

6. ### AI IncLawnSite Fanaticfrom Southern NHPosts: 25,393

This is actualy a lot easier then it would appear. Take your outside # and divide it by # of peices. Take your inside # and divide it by # of peices and that will give you your angle.

7. ### DVS HardscaperLawnSite Fanaticfrom County JailPosts: 6,417

I'm gettin a kick out of that LITTLE hole was dug with a machine! Christ, it took more time to load and unload the machine than it would have for 2 of my guys to dig it

Gotta love white people.........

,

8. ### Dirt Digger2LawnSite Silver Memberfrom PAPosts: 2,396

the little machine was also used to rip up the bulkhead board, dig the drain pipe line out from the pond, and move a pile of dirt...

but she sure is cute though

9. ### cetLawnSite Memberfrom TorontoPosts: 89

This looks like a pretty hard way to figure it out.

Only problem is 1.000-0.776=0.224 not 0.3243. 1/2 of .224 is .112

I think the answer is what I gave you in my first post.

10. ### capelawncare.comLawnSite Fanaticfrom Cape Coral- Ft Myers FLPosts: 8,136

Looks like a long commute from Pa to that job...