A cylindrical rod has an curved surface area of 4,900 cm². If the length of the rod is 97 cm, then the radius (in cm) of the rod, correct to two places of decimal, is:
Take $$\pi = \frac{22}{7}$$​

Correct option is D

Given:

Curved Surface Area (CSA) = 4,900 cm²

Height (length) h = 97 cm

Formula Used:

Curved Surface Area of a cylinder = 2πrh

Solution: 

CSA of cylinder = $$2 \times \frac{22}{7} \times r \times 97$$ 

4900 = $$2 \times \frac{22}{7} \times r \times 97$$​

r =$$\frac{4900}{2 \times \frac{22}{7} \times 97}$$​   $$= \frac{34300}{4268} \approx 8.039$$​​

r = 8.04 cm