Question

7. From a solid cylinder whose height is 2.4cm and diameter 1.4cm a conical
x cavity of the same height and same diameter is hollowed out. Find the TSA of
solid to nearest cm?​

Answer 1

Answer:

18 sq.cm.

Step-by-step explanation:

Height of the cylinder, h = 2.4 m.

Diameter of the cylinder, d = 1.4 m.

∴ Radius, r = 0.7 m.

(i) Outer Curved surface area of cylinder = 2πrh

=2× 22 × (0.7) ×2.4

7

= 44. × 0.24 = 10.56 cm2 .

(ii) Area of base of = πr2

(iii) Inner surface area of cylinder, = πrl

=22 ×0.7×√(0.7)^2 + (2.4)^2

7

=22 × 0.7 ×2.5

7

= 5.5 cm2

∴ Total surface area of newly formed cube

= 10.56 + 1.54 + 5.5 = 17.6 cm2 .

∴ Nearest value is 18 sq.cm.