Question

A semi-circle of diameter 56 cm is changed to the shape of a cone. Find the radius and

the curved surface area of the cone so formed.​

Answer 1

Step-by-step explanation:

Diameter of semi circle = 56 cm

Radius of semi circle = 56/2 cm => 28 cm

$circumference \: = \: \pi\: r$

Circumference = 22/7 × 28 cm

= 88 cm

On converting to cone, Radius will become slant height and circumference will become circumference of base of cone.

C = 2 × 22/7 × r

88 = 2 × 22/7 × r

r = 14 cm

Radius of cone = 14 cm

CSA of cone = π r l unit²

= 22/7 × 14 × 28

= 1232 cm²

Therefore, Radius of cone = 14 cm and CSA of cone = 1232 cm²

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