There is a solid cylinder of base radius 5 cm and height 10 cm. From one of the flat ends of the solid cylinder a hemispherical depression having same radius as cylinder is hollowed out. What is the total surface area (in sq.cm) of this new solid?
The total surface area of the above solid = C.S.A of the hemispherical depression + C.S.A of the cylinder + Base area of the cylinder
C.S.A of hemispherical depression =2πr2=2π(5)2=50π cm2
C.S.A of cylinder =2πrh=2π×5×10=100π cm2
Base area of cylinder = πr2
= π(5)2
= 25π cm2
Total surface area = C.S.A of hemispherical depression + C.S.A of cylinder + Base area of cylinder =50π+100π+25π =175π