The curved surface area of a cone is 2970 cm², and its diameter is 70 cm. What is its total surface area (in cm²)?
Use $$\pi$$ = $$\frac{22}{7}$$​

Correct option is A

Given:

Curved surface area (C.S.A) of the cone = 2970 cm²

Diameter of the cone = 70 cm

Formula Used:

Curved surface area (C.S.A) of a cone = πrl

Total surface Area of cone(T.S.A) = πr(r + l) = CSA + πr²

Solution:

Diameter = 70 cm, so

Radius r = $$\frac{70}{2}$$​ = 35 cm

Now, from the CSA of cone;

2970 = $$\frac{22}{7} \times 35 \times l$$​​

2970 = $$110 \times l$$​​

l = $$\frac{2970}{110}$$​ = 27 cm

Now, 

T. S.A of cone = 2970 + $$\frac{22}{7} \times 35^2$$​​

= 2970 + $$\frac{22}{7} \times 1225$$​​

= 2970 + 3850 = 6820 cm²