The hemispherical bowl has three surfaces to calculate : the interior hemisphere (rint=7) cm , the exterior hemisphere (rext=7+1=8) cm and the annular ( ring shaped ) top edge (rext,rint) Area of hemisphere = 2πr2 and area of annular = π(r2ext−r2int) Total surface area of hemisphere is the sum of these 3 areas = [2π(7)2]+[2π(8)2]+[π(82−72)] = π(98+128+64−49)=241π = 241×