Given a hollow hemisphere with an inner radius of 7 cm and an outer radius of 8 cm, what is its entire surface area?
Show answer & explanation
Correct answer: D
Explanation
Inner radius (r) = 7 cm, Outer radius (R) = 8 cm
Total Surface Area = 2πR² + 2πr² + π(R² − r²)
= 2π(8²) + 2π(7²) + π(8² − 7²)
= 2π(64) + 2π(49) + π(64 − 49)
= 128π + 98π + 15π
= 241π cm²