Question

tolfo wants to find the area of a circle with a diameter of 18 cm. which expressions can he use to find the area of the circle in square centimeters? choose all the correct answers. 1) 2 • 9 • π 2) 18 • π 3) 3 • 3 • π 4) 18² • π 5) 9² • π the circumference of a circular trampoline is 50 π in. how can the radius of the trampoline be determined? the circumference of a circle is equal to the diameter multiplied by ______?

Explanation:

Step1: Recall circle - area formula

The formula for the area of a circle is $A = \pi r^{2}$, where $r$ is the radius of the circle. Given the diameter $d = 18$ cm, the radius $r=\frac{d}{2}=\frac{18}{2}=9$ cm.

Step2: Substitute radius into formula

Substitute $r = 9$ into the area formula $A=\pi r^{2}$, we get $A = 9^{2}\cdot\pi=81\pi$ square - centimeters.

Answer:

$9^{2}\cdot\pi$