Question

1. the formula for the area of a circle is_____.

a. $2\pi r^{2}$
b. $d\pi$
c. $\pi r^{2}$
d. $2\pi r$

Explanation:

Step1: Recall the formula for the area of a circle

The formula for the area of a circle is \( A=\pi r^{2} \), where \( r \) is the radius of the circle.

Step2: Analyze each option

• Option a: \( 2\pi r^{2} \) is not the formula for the area of a circle.
• Option b: \( d\pi=\pi\times d \) (where \( d = 2r \)) gives the circumference of a circle (\( C=\pi d \)), not the area.
• Option c: \( \pi r^{2} \) is the correct formula for the area of a circle.
• Option d: \( 2\pi r \) is the formula for the circumference of a circle (\( C = 2\pi r \)), not the area.

Answer:

C. \( \pi r^{2} \)