Question

Find the total surface area of a cone, if its slant height is 21 m and diameter of its base is 24m.​

Answer 1

Answer:

1244.57 meter square

Step-by-step explanation:

Given,

Slant height of cone is l=21 m.

Diameter of its base is d=24 m.

hence, radius of its base is r=

2

d

=12 m.

Now, the total surface area of cone is given by

S=πrl+πr

2

S=π(rl+r

2

)

S=π(12×21+12

2

)

S=π(252+144)

S=

7

22

×396

hence, S=1244.57 m

2

Answer 2

Answer:

829.71 m (approximately)

Step-by-step explanation:

→ Given, D = 24 m

R = 24 / 2 → R = 12 m

l = 21 m

→ Total Surface Area of cone = πrl + πr

→ πrl + πr

→ π (rl + r)

→ 22 / 7 (12 × 21 + 12)

→ 22 / 7 (252 + 12)

→ 22 / 7 (264)

→ 22 / 7 × 264

→ 5808/7

→ 829.71 m (approximately)

→ Thus, the Total Surface Area of cone with slant height

21 m and diameter 24 m is 829.71 m (approximately)

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