Question

The perimeter of a semicircle whose radius is \(3r\) is

• A. \(3\pi r + 3r\)
• B. \(3\pi r + 6r\)
• C. \(3\pi r + 9r\)
• D. \(3\pi r\)

Hint:

For semicircle perimeter: add half circumference (\(\pi r\)) and diameter (\(2r\)).

Answer 1

The Correct Option is A

Step 1: Formula for semicircle perimeter.
Perimeter \(= \pi r + 2r\) (half the circumference plus the diameter).
Step 2: Substitute radius \(3r\).
\[ P = \pi (3r) + 2(3r) = 3\pi r + 6r \]
Step 3: Match with options.
Oops—actual correct choice is (2) \(3\pi r + 6r\).