Question

Find the circumference and the area of a circle with a radius of 9 .

Answer 1

Step-by-step explanation: To find the circumference, remember that the formula for the circumference of a circle is C = 2πr.

Since we're given that the radius of our circle is 9,

we have 2π(9) or 18π.

So the circumference of the circle is 18π.

To find the area of the circle, remember that the formula

for the area of a circle is A = πr².

Since we're given that the radius of our circle is 9,

we have π(9)² or π(81) which is written as 81π.

So the area of the circle is 81π.

Answer 2

Circumference ≈ 56.52 units

C = π x d (you can remember this by saying “chocolate pies are delicious”)

C = π x 18 (diameter is radius x 2 or radius + radius)

(you can round π to 3.14)

C ≈ 56.52 units

Area ≈ 254.34 units squared

A = π x r^2 (you can remember this by saying “apple pies are too” [building off of ‘chocolate pies are delicious‘])

A = π x 9^2

A = π x 81

(you can round π to 3.14)

A ≈ 254.34 units squared