The total surface area of a hemisphere is 462 cm2. The diameter of this hemisphere is:
Answer & explanation
Correct answer: option 4
We know that,
Total surface area of a hemisphere = 3πr2
We have,
The total surface area of a hemisphere = 462
3 πr2 = 462
= 3 × \(\frac{22}{7}\) × r2 = 462
= r2 = 462 × \(\frac{7}{22}\) × \(\frac{1}{3}\)
= r = \(\sqrt {49}\) = 7 cm
and the diameter = 7 × 2 = 14 cm