Question

The radius of the base of a cylinder is 3.5 cm. If its height is 8.4 cm, then its curved surface area will be

• A. $54.8\pi$ cm$^2$
• B. $56.4\pi$ cm$^2$
• C. $56.6\pi$ cm$^2$
• D. $58.8\pi$ cm$^2$

Hint:

Always remember: Curved Surface Area of a Cylinder = $2\pi r h$, and Total Surface Area = $2\pi r (r + h)$.

Answer 1

The Correct Option is D

Step 1: Recall the formula for curved surface area (CSA) of a cylinder.
\[ \text{CSA} = 2\pi r h \] Step 2: Substitute the given values.
\( r = 3.5 \text{ cm}, \, h = 8.4 \text{ cm} \) \[ \text{CSA} = 2\pi \times 3.5 \times 8.4 \] Step 3: Simplify.
\[ \text{CSA} = 2\pi \times 29.4 = 58.8\pi \text{ cm}^2 \] Step 4: Conclusion.
Hence, the curved surface area of the cylinder is \( 58.8\pi \, \text{cm}^2 \).