Question

A toy is in the shape of a hemisphere surmounted by a cone. If radius of base of the cone is 3 cm and its height is 4 cm, the total surface area of the toy is

• A. 33 \(\pi cm^2\)
• B. 42 \(\pi cm^2\)
• C. 66 \(\pi cm^2\)
• D. 56 \(\pi cm^2\)

Answer 1

The Correct Option is A

Surface area of hemisphere=2\(\pi\)r²
= 2\(\pi\)(3)² = 18\(\pi\)сm²
Surface area of cone = \(\pi\)rl
l=\(\sqrt{4^2 + 3^2}\) = 5
Area \(\pi\)×3×5=15\(\pi\) cm²
Total surface area = 18\(\pi\)+ 15\(\pi\)= 33\(\pi\) cm²
So the correct option is (A)