Question

finding the area of a circle continued

find the missing measurements. use 3.14 for π. show your work.

7 radius: 6 mm
diameter: 12 mm
area: ≈ 113.04 mm²
8 radius:
diameter: 16 ft
area:
9 radius: 12 cm
diameter: 24 cm
area:
10 radius:
diameter: 2 km
area:

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.

Step2: Solve for problem 7

Given $r = 6$ mm, substitute into the formula: $A=3.14\times6^{2}=3.14\times36 = 113.04$ mm².

Step3: Solve for problem 8

Given diameter $d = 16$ ft, find the radius $r=\frac{d}{2}=\frac{16}{2}=8$ ft. Then find the area $A = 3.14\times8^{2}=3.14\times64 = 200.96$ ft².

Step4: Solve for problem 9

Given $r = 12$ cm, find the area $A=3.14\times12^{2}=3.14\times144 = 452.16$ cm².

Step5: Solve for problem 10

Given diameter $d = 2$ km, find the radius $r=\frac{d}{2}=\frac{2}{2}=1$ km. Then find the area $A = 3.14\times1^{2}=3.14$ km².

Answer:

1. Area: $113.04$ mm²
2. Radius: 8 ft, Area: $200.96$ ft²
3. Area: $452.16$ cm²
4. Radius: 1 km, Area: $3.14$ km²