Question

find the total surface area of a cone, if it's slant height is 21m and diameter of its base is 24m​

Answer 1

Answer:

We know that Total surface area of a cone = πr (l + r) By substituting the values Total surface area of a cone = (22/7) × 12 (21+12) On further calculation Total surface area of a cone = (22/7) × 12 × 33 So we get Total surface area of a cone = 1244.57 m2 Therefore, the total surface area of a cone is 1244.57 m2.Read more on Sarthaks.com - https://www.sarthaks.com/721544/find-the-total-surface-area-of-cone-if-its-slant-height-is-21m-and-diameter-of-its-base-is-24m

Answer 2

radius of its base,is =r=d/2=12

s=pi rl+pi r²

S=pi(rl+r²)

s=pi(12×21+12²)

S=pi(252+144)

s=22/7×396

hence ,S=1244.57m²

ok it is answer