Aptitude - Volume and Surface Area - Discussion

Discussion Forum : Volume and Surface Area - General Questions (Q.No. 13)
13.
What is the total surface area of a right circular cone of height 14 cm and base radius 7 cm?
344.35 cm2
462 cm2
498.35 cm2
None of these
Answer: Option
Explanation:

h = 14 cm, r = 7 cm.

So, l = (7)2 + (14)2 = 245 = 75 cm.

Total surface area = rl + r2
= 22 x 7 x 75 + 22 x 7 x 7 cm2
7 7
= [154(5 + 1)] cm2
= (154 x 3.236) cm2
= 498.35 cm2.

Discussion:
11 comments Page 2 of 2.

Sachin K C said:   4 years ago
l is the slant height of the cone
Formula to find slant height of the cone is √(r^2+h^2).


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