The height of a right circular cylinder is 23 cm and circumference of its base is 77 cm. What is its curved surface area?

Correct option is B

Given: 

height (h) of the cylinder = 23 cm,  

circumference of the cylinder  = 77 cm 

Formula Used: 

Circumference of the cylinder base =  $$2\pi{r}$$ 

Curved Surface area (C.S.A)  of the cylinder = $$2 \pi r h$$ 

where, r is radius

Solution:  

Circumference of the cylinder base = 77 

$$2\pi{r}$$​ = 77

r = $$\frac{77}{2\pi}$$  

So, 

Curved Surface area of the cylinder = $$2\pi {rh}$$

 = $$2\pi\times\frac{77}{2\pi}\times23$$ 

= $$77\times23$$ 

= 1771

Thus, Option (b). 1771 is correct.