Q.The lateral surface area of a right circular cone is \( \sqrt{5} \) times the area of its base. What is the ratio of the cone’s height to the radius of its base?

Let the height of the cone be \(h\) units and the radius be \(r\) units. ∴ According to the question, \(πrl = \sqrt{5} × πr^2\) i.e., \(l = \sqrt{5}r\) i.e., \(\sqrt{h^2 + r^2} = \sqrt{5}r\) i.e., \(h^2 + r^2 = 5r^2\) i.e., \(h^2 = 4r^2\) i.e., \(\cfrac{h^2}{r^2} = \cfrac{4}{1}\) i.e., \(\cfrac{h}{r} = \cfrac{2}{1}\) i.e., \(h : r = 2 : 1\) ∴ The ratio of the cone’s height to its radius is \(2 : 1\).
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