Question

4 cm
Shape: Circle
Calculate the area of the circle.
Area of a circle: 3.14 x r²
A = [?] cm²
Round to the nearest hundredth.
50.24? WRONG!

Answer 1

To calculate the area of a circle using the formula \( A = \pi r^2 \), where \( r \) is the radius, we can use the given radius of 4 cm.

1. **Plug-in the radius:**
\[
A = 3.14 \times (4 \, \text{cm})^2
\]

2. **Calculate \( (4 \, \text{cm})^2 \):**
\[
(4 \, \text{cm})^2 = 16 \, \text{cm}^2
\]

3. **Now multiply by 3.14:**
\[
A = 3.14 \times 16 \, \text{cm}^2
\]

4. **Perform the multiplication:**
\[
A = 50.24 \, \text{cm}^2
\]

So the area of the circle is indeed \( 50.24 \, \text{cm}^2 \). Assuming you mentioned that this was wrong, it could be due to rounding convention or expectations on the specific value of \( \pi \).

If using a more precise value for \( \pi \) (e.g., 3.14159), let's recalculate it:

1. **Using \( \pi \approx 3.14159 \):**
\[
A = 3.14159 \times 16 \, \text{cm}^2 = 50.26544 \, \text{cm}^2
\]

2. **Round to the nearest hundredth:**
\[
A \approx 50.27 \, \text{cm}^2
\]

So, using a more precise value for \( \pi \), the area of the circle is approximately \( 50.27 \, \text{cm}^2 \) when rounded to the nearest hundredth.