Question

The total surface area of a hemisphere solid having radius 7 cm is:

• A. \( 616 \, \text{cm}^2 \)
• B. \( 462 \, \text{cm}^2 \)
• C. \( 154 \, \text{cm}^2 \)
• D. \( 77 \, \text{cm}^2 \)

Hint:

For the surface area of a hemisphere, use the formula \( A = 3\pi r^2 \), where \( r \) is the radius of the hemisphere.

Answer 1

The Correct Option is B

Step 1: Formula for the surface area of a hemisphere.
The total surface area of a hemisphere is given by: \[ A = 3 \pi r^2 \] Step 2: Substitute the radius value into the formula.
We are given \( r = 7 \, \text{cm} \), so substitute this value into the formula: \[ A = 3 \pi (7)^2 = 3 \pi (49) = 147 \pi \] Step 3: Calculate the value.
Approximating \( \pi \approx 3.1416 \), we get: \[ A \approx 147 \times 3.1416 = 462 \, \text{cm}^2 \] Thus, the total surface area is \( 462 \, \text{cm}^2 \).