Verified answer

Answer:

1244.57 m^2

Step-by-step explanation:

to better understand the question please check the attached image

We are given that the slant height of the cone is 21 m and diameter if its base is 24 m.

We need the radius of the base to find the total surface area.

Radius = half of the diameter = 24 ÷ 2 = 12

Total Surface area of Cone = πr² + πrl

Taking ‘πr’ common, we get

= πr × (l + r)

= 22 / 7 × 12 (21 + 12)

= 22 × 12 / 7 (33)

= 22 × 12 × 33 / 7

= 8712 / 7

= 1,244.57143 ...

Therefore, the total surface of a cone with slant height 21 m and diameter 24 m is 1244.57 square meters.

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