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: 8 ft
diameter: 16 ft
area 200.96 ft²
9 radius 12 cm
diameter: 24 cm
area 452.16 cm²
10 radius: 1 km
diameter: 2 km
area: 3.14 km²

Explanation:

Step1: Recall area formula

The formula for the area of a circle is $A = \pi r^{2}$, where $r$ is the radius and $\pi\approx3.14$.

Step2: Calculate for radius 6 mm

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

Step3: Calculate for radius 8 ft

Given $r = 8$ ft, $A = 3.14\times8^{2}=3.14\times64=200.96$ ft$^{2}$.

Step4: Calculate for radius 12 cm

With $r = 12$ cm, $A=3.14\times12^{2}=3.14\times144 = 452.16$ cm$^{2}$.

Step5: Calculate for radius 1 km

Since $r = 1$ km, $A=3.14\times1^{2}=3.14$ km$^{2}$.

Answer:

For radius 6 mm, area is 113.04 mm$^{2}$.
For radius 8 ft, area is 200.96 ft$^{2}$.
For radius 12 cm, area is 452.16 cm$^{2}$.
For radius 1 km, area is 3.14 km$^{2}$.