math problems?

1. A triangularhole that has sides lengths of 3.97 ft 4.24 ft and 5.00 ft and is 2ft deep. Find the volume of the hole.

Using Heron's formula

The shape of the triangle is determined by the lengths of the sides alone. Therefore the area S also can be derived from the lengths of the sides. By Heron's formula:

S = \sqrt{s(s-a)(s-b)(s-c)}

where s = ½ (a + b + c) is the semiperimeter, or half of the triangle's perimeter.

calculate s first (use 1/2(a+b+c) formula) -> you should get 6.605

use this value for the lowercase s in Heron's formula above

2.how many 7-in square tiles will cover a floor 28ft by 14ft

- first, convert to inches

14ft becomes 168 inches

28ft becomes 336 inches

divide inches by 7 - this will tell you how many rows of 7 inch tiles you can fit...

168/7 = 24 (7-in tiles across)

336/7 = 48 (7-in tiles deep)

multiply 24*48 and you get the number of 7-in tiles which will fit into a 28' x 14' floor

3. the slant height of a cone is 21.8in and the diameter is of the base is 18.4in how high is the cone.

- pythagorean theorem works here... slant ht is the hypotenuse, half of diameter is one leg... solve for the other leg....

a^2 + 9.2^2 = 21.8^2

a^2 + 84.64 = 475.24

a^2 = 475.24-84.64

a^2=390.6

a=19.76 (approx.)