Questions: Consider the following figure. Give both exact values and approximations to the nearest hundredth.
(a) Find the circumference (in cm ) of the figure.
exact
cm
approximation
cm
(b) Find the area (in cm^2 ) of the figure.
exact
cm^2
approximation
cm^2
Transcript text: Consider the following figure. Give both exact values and approximations to the nearest hundredth.
(a) Find the circumference (in cm ) of the figure.
exact $\square$
cm
approximation $\square$
cm
(b) Find the area (in $\mathrm{cm}^{2}$ ) of the figure.
exact $\square$
$\mathrm{cm}^{2}$
approximation $\square$
$\mathrm{cm}^{2}$
Solution
Solution Steps
Step 1: Identify the given information
The radius of the circle is given as 8 cm.
Step 2: Calculate the exact circumference
The formula for the circumference of a circle is \( C = 2\pi r \).
Substitute \( r = 8 \) cm:
\[ C = 2\pi \times 8 = 16\pi \text{ cm} \]
Step 3: Calculate the approximate circumference
Use the approximation \( \pi \approx 3.14 \):
\[ C \approx 16 \times 3.14 = 50.24 \text{ cm} \]
Step 4: Calculate the exact area
The formula for the area of a circle is \( A = \pi r^2 \).
Substitute \( r = 8 \) cm:
\[ A = \pi \times 8^2 = 64\pi \text{ cm}^2 \]
Step 5: Calculate the approximate area
Use the approximation \( \pi \approx 3.14 \):
\[ A \approx 64 \times 3.14 = 200.96 \text{ cm}^2 \]