Math worksheet for calculating the area of circles using radius measurements.

To solve the problem of finding the area of each circle using the given radius measurements, we will use the formula for the area of a circle:

\[
A = \pi r^2
\]

Where:
- \( A \) is the area of the circle.
- \( r \) is the radius of the circle.
- \( \pi \) (pi) is approximately 3.14159.

We will calculate the area for each circle and round the answers to 1 decimal place.

Step-by-Step Calculations:

#### 1) Radius = 5 cm
\[
A = \pi r^2 = \pi (5)^2 = 3.14159 \times 25 = 78.53975 \approx 78.5 \, \text{cm}^2
\]

#### 2) Radius = 10 in
\[
A = \pi r^2 = \pi (10)^2 = 3.14159 \times 100 = 314.159 \approx 314.2 \, \text{in}^2
\]

#### 3) Radius = 3 ft
\[
A = \pi r^2 = \pi (3)^2 = 3.14159 \times 9 = 28.27431 \approx 28.3 \, \text{ft}^2
\]

#### 4) Radius = 2 yd
\[
A = \pi r^2 = \pi (2)^2 = 3.14159 \times 4 = 12.56636 \approx 12.6 \, \text{yd}^2
\]

#### 5) Radius = 8 in
\[
A = \pi r^2 = \pi (8)^2 = 3.14159 \times 64 = 201.06176 \approx 201.1 \, \text{in}^2
\]

#### 6) Radius = 6 ft
\[
A = \pi r^2 = \pi (6)^2 = 3.14159 \times 36 = 113.09724 \approx 113.1 \, \text{ft}^2
\]

#### 7) Radius = 9 cm
\[
A = \pi r^2 = \pi (9)^2 = 3.14159 \times 81 = 254.46909 \approx 254.5 \, \text{cm}^2
\]

#### 8) Radius = 16 ft
\[
A = \pi r^2 = \pi (16)^2 = 3.14159 \times 256 = 804.24776 \approx 804.2 \, \text{ft}^2
\]

#### 9) Radius = 12 in
\[
A = \pi r^2 = \pi (12)^2 = 3.14159 \times 144 = 452.38934 \approx 452.4 \, \text{in}^2
\]

#### 10) Radius = 11 yd
\[
A = \pi r^2 = \pi (11)^2 = 3.14159 \times 121 = 379.94119 \approx 380.0 \, \text{yd}^2
\]

#### 11) Radius = 20 in (Note: Diameter is given as 20 in, so radius = 20 / 2 = 10 in)
\[
A = \pi r^2 = \pi (10)^2 = 3.14159 \times 100 = 314.159 \approx 314.2 \, \text{in}^2
\]

#### 12) Radius = 14 ft
\[
A = \pi r^2 = \pi (14)^2 = 3.14159 \times 196 = 615.75164 \approx 615.8 \, \text{ft}^2
\]

Final Answers:

\[
\boxed{
\begin{array}{ll}
1) & 78.5 \, \text{cm}^2 \\
2) & 314.2 \, \text{in}^2 \\
3) & 28.3 \, \text{ft}^2 \\
4) & 12.6 \, \text{yd}^2 \\
5) & 201.1 \, \text{in}^2 \\
6) & 113.1 \, \text{ft}^2 \\
7) & 254.5 \, \text{cm}^2 \\
8) & 804.2 \, \text{ft}^2 \\
9) & 452.4 \, \text{in}^2 \\
10) & 380.0 \, \text{yd}^2 \\
11) & 314.2 \, \text{in}^2 \\
12) & 615.8 \, \text{ft}^2 \\
\end{array}
}
\]