Question

Area of the base of a right circular cylinder is 9\( \pi \) cm\(^2\). Radius of its base will be

• A. 3 cm
• B. 6 cm
• C. 2 cm
• D. 4 cm

Hint:

Always pay attention to the units given in the question and make sure your answer has the correct units. In this case, the area is in cm\(^2\), so the radius will be in cm.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
The base of a right circular cylinder is a circle. The problem gives the area of this circular base and asks for its radius.
Step 2: Key Formula or Approach:
The formula for the area of a circle with radius \(r\) is:
\[ \text{Area} = \pi r^2 \] Step 3: Detailed Explanation:
We are given that the area of the base of the cylinder is \( 9\pi \) cm\(^2\).
Using the formula for the area of a circle:
\[ \pi r^2 = 9\pi \] To find the radius \(r\), we can solve this equation. Divide both sides by \( \pi \):
\[ r^2 = 9 \] Take the square root of both sides. Since radius must be a positive value:
\[ r = \sqrt{9} \] \[ r = 3 \] Step 4: Final Answer:
The radius of its base will be 3 cm.