Question

circumference = 72.2
8.
radius = 12
area =
circumference =
circumference = 50.2
9.
diameter = 14
area =
circumference =
11.
12.

Explanation:

Step1: Calculate the area and circumference for the circle with radius \( r = 12 \)

• Area formula: \( A=\pi r^{2} \)
• Substitute \( r = 12 \): \( A=\pi\times12^{2}=\pi\times144\approx3.14\times144 = 452.16 \)
• Circumference formula: \( C = 2\pi r \)
• Substitute \( r = 12 \): \( C=2\times\pi\times12=24\pi\approx24\times3.14 = 75.36 \)

Step2: Calculate the area and circumference for the circle with diameter \( d = 14 \)

• First, find the radius \( r=\frac{d}{2}=\frac{14}{2}=7 \)
• Area formula: \( A=\pi r^{2} \)
• Substitute \( r = 7 \): \( A=\pi\times7^{2}=\pi\times49\approx3.14\times49 = 153.86 \)
• Circumference formula: \( C=\pi d \) (or \( C = 2\pi r \))
• Using \( C=\pi d \), substitute \( d = 14 \): \( C=\pi\times14\approx3.14\times14 = 43.96 \)

Answer:

For problem 8 (radius \( r = 12 \)):

• Area \( = 452.16 \)
• Circumference \( = 75.36 \)

For problem 9 (diameter \( d = 14 \)):

• Area \( = 153.86 \)
• Circumference \( = 43.96 \)