Question

7)
radius =
diameter =
area =
c =
8)
radius =
diameter =
area =
c =
9)
radius =
diameter =
area =
c =

Explanation:

7)

Step1: Find radius and diameter

Given diameter \(d = 30m\). Radius \(r=\frac{d}{2}=\frac{30}{2}=15m\).

Step2: Calculate area

Area formula \(A=\pi r^{2}\). Substitute \(r = 15\), \(A=\pi\times15^{2}=225\pi\approx225\times3.14 = 706.5m^{2}\).

Step3: Calculate circumference

Circumference formula \(C=\pi d\). Substitute \(d = 30\), \(C = 30\pi\approx30\times3.14=94.2m\).

8)

Step1: Find radius and diameter

Given radius \(r = 8cm\). Diameter \(d = 2r=2\times8 = 16cm\).

Step2: Calculate area

Area formula \(A=\pi r^{2}\). Substitute \(r = 8\), \(A=\pi\times8^{2}=64\pi\approx64\times3.14 = 200.96cm^{2}\).

Step3: Calculate circumference

Circumference formula \(C = 2\pi r\). Substitute \(r = 8\), \(C=2\pi\times8=16\pi\approx16\times3.14 = 50.24cm\).

9)

Step1: Find radius and diameter

Given diameter \(d = 20ft\). Radius \(r=\frac{d}{2}=\frac{20}{2}=10ft\).

Step2: Calculate area

Area formula \(A=\pi r^{2}\). Substitute \(r = 10\), \(A=\pi\times10^{2}=100\pi\approx100\times3.14=314ft^{2}\).

Step3: Calculate circumference

Circumference formula \(C=\pi d\). Substitute \(d = 20\), \(C = 20\pi\approx20\times3.14 = 62.8ft\).

Answer:

1. Radius \(= 15m\), Diameter \(=30m\), Area \(\approx706.5m^{2}\), \(C\approx94.2m\)
2. Radius \(=8cm\), Diameter \(=16cm\), Area \(\approx200.96cm^{2}\), \(C\approx50.24cm\)
3. Radius \(=10ft\), Diameter \(=20ft\), Area \(\approx314ft^{2}\), \(C\approx62.8ft\)