Question

from a solid cylinder of height 20 cm and diameter 12cm a conical cavity of height 8cm and radius 6cm is hollowed out. find the TSA of remaining solid .
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Answer 1

see attached file for the answer

Answer 2

EXPLANATION.

Height of solid cylinder = 20 CM.

Diameter of solid cylinder = 12 CM

radius of solid cylinder = d/2 = 12/2 = 6 CM.

height of conical cavity = 8 cm.

radius of conical cavity = 6 cm.

To find the TSA of remaining solid.

Lateral height of the cone.

L = √H² + R²

L = √(8)² + (6)²

L = √64 + 36

L = √100

L = 10

TSA of remaining solid.

= CSA of cylinder + Area of base of cylinder

+ CSA of cone.

A = 2πrh + πr² + πRL

A = π ( 2rh + r² + RL)

A = π ( 2 X 6 X 20 + (6)² + 6 X 10 )

A = π ( 240 + 36 + 60 )

A = π ( 336)

A = 1055.57 cm²