Question

aleks circumference and area of circles review (morgan)
question 13 of 20 (1 point) | question attempt: 3 of unlimited
your answer is incorrect.

• area: the value in your answer is incorrect.
• circumference: the value in your answer is incorrect.

find the area and the circumference of a circle with diameter 4 mm.
write your answers in terms of π, and be sure to include the correct units in your answers.
your answer
(a) area:
(b) circumference:

Explanation:

Step1: Find the radius for area

The diameter \( d = 4 \) mm, so radius \( r=\frac{d}{2}=\frac{4}{2} = 2 \) mm. The formula for the area of a circle is \( A=\pi r^{2} \). Substitute \( r = 2 \): \( A=\pi(2)^{2}=\pi\times4 = 4\pi \) square millimeters.

Step2: Find the circumference

The formula for the circumference of a circle is \( C=\pi d \) (or \( C = 2\pi r \)). Substitute \( d = 4 \) mm: \( C=\pi\times4=4\pi \) millimeters.

Answer:

(a) Area: \( 4\pi \) square millimeters
(b) Circumference: \( 4\pi \) millimeters