How do you find perimeter, circumference, and area?

Question

If the area of a circle is 49π (pie), how do you find the radius?
If the area of a square is 25, how do you find the perimeter?
If the length of each side of a square is 12, how do you find the perimeter?
If the length of a rectangle is 8 and the area is 40, how do you find the width?
If the area of a circle is 36π (pie), how do you find the diameter?
If the diameter of a circle is 20, how do you find the area?
If the base of a triangle is 14 and height is 8, how do you find the area?
If the base of a rectangle is 14 and the height is 8,how do you find the area?
If the area of a circle is 100π (pie), how do you find the circumference?

Answer 1

use these formulas

 

Area of circle = πr² with r = radius

Circumference of circle = 2πr = πd with d = diameter

diameter = 2 x radius

 

Area of square = s² with s = length of side

Perimeter of square = 4s

 

Area of rectangle = length x width

 

Area of triangle = (1/2) x base x height

 

 

Answer 2

Use the equations and work backwards.

For example... Area of a circle = πr²

So, in your 1st example, if πr² = 49π, divide both sides by π.

Then, if r² = 49, take the square root of both sides.

r = 7.