Question

A cone has a diameter of 9 inches and a height of 12 inches. Find the volume of the cone to the nearest tenth.

.
Find the area of a circle with d = 19 km. Use 3.14 for ππ. Round to the nearest tenth.

Area is the number of cubic units needed to fill a space. True or False

Answer 1

1)
The formula for calculating the cone volume is:

`V = ( \pi *r^2*h)/(3)`

Data:
V (volume) = ?
h (height) → h = 12 in
d (diagonal) = 9 in , if: d = 2*r , soon: 9 = 2*r → 2r = 9 → r = 9/2 → r = 4.5 in
Use:
`\pi \approx 3.14`

Solving:

`V = ( \pi *r^2*h)/(3)`

`V = ( 3.14 *4.5^2*12)/(3)`

`V = ( 3.14 *20.25*12)/(3)`

`V = (763.02)/(3)`

`\boxed{\boxed{V = 254.34\:in^3}}\end{array}}\qquad\quad\checkmark`

2)
The circle area formula is:
`A = \pi * r^2`

Data:
A (area) = ?
d (diagonal) = 19 Km , if: d = 2*r , soon: 19 = 2*r → 2r = 19 → r = 19/2 → r = 9.5 Km
Use:
`\pi \approx 3.14`

Solving:

`A = \pi * r^2`

`A = 3.14*9.5^2`

`A = 3.14*90.25`

`\boxed{\boxed{A = 283.385\:Km^2}}\end{array}}\qquad\quad\checkmark`


3) False, because it's the volume, the number of cubic units needed to fill a space.