Concrete can be bought by the cubic yard. How much will it cost to pour a slab 17ft by 17ft by 2 inches for a patio if concrete costs 40.00$ per cubic yard? (I keep getting an answer that is way to high.)
$40 per 27 cubic feet.
17 * 17 * 1/6 = 289/6 = 48.16... cubic feet
48.16... / 27 = 1.78 batches of concrete
Since you can only purchase in increments of cubic yards, you round up to 2
2 * $40 = $80
EDIT: I must have typoed when I initially did 17 * 17 * 1/6
Another one is a triangular prism with a regular square base that has all sides of the base 24ft and a slant height of 20 ft. I need the volume, so I need to find the actual height.
Wouldn't a triangular prism have a triangular base? I am confused.
Last one for now: The volume of a sphere is 3000Ï€m3. What is the surface area to the nearest square. (I keep getting way off from the options, which are 2158m squared, 37699m squared, 165m squared and 1079m squared)
Find the radius
Volume = 4/3 * Ï€ * r3
3000Ï€ = 4/3 Ï€ * r3
2250 = r3
13.1 = r
Surface Area = 4 * Ï€ * r2
A = 4 * 3.14159 * 171.7
A = 2157.7 m2