In a right circular cone, √(l + r)(l - r) = (A) slant height (B) vertical height
In a right circular cone, \(\sqrt{(l+r)(l-r)}\) =
(A) slant height
(B) vertical height
(C) radius of the base
(D) diameter of the base
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2 Answers
Correct option is: (B) vertical height
In right circular cone, we have
r = Radius of base of the cone,
h = Vertical height of the cone
l = slant height of the cone
Now, \(\sqrt{(l + r)(l - r)}\) = \(\sqrt {l^2-r^2}\) (\(\because\) (a+b) (a-b) = \(a^2-b^2\))
= \(\sqrt {h^2}\) (\(\because\) \(l^2 = r^2 + h^2 = l^2 -r^2 = h^2\))
= h which is vertical height of the right circular cone.
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