The internal and external radius of a hollow hemispherical vessel are 7 cm and 8 cm respectively. What is total surface area of the vessel?

1204 cm² 365.85 cm² 726.96 cm² 756.74 cm²

756.74 cm²

T.S.A. = C.S.A. of (inner + outer) hemispherical + area of ring          = 2\(\pi \) (R2 + r2) + \(\pi \) (R2 - r2)           = 3\(\pi \) R2 + \(\pi \) r2          = \(\pi \) (3 × (8)2 + (7)2)          = 3.14 × 241 = 756.74 cm2