Radius of the base and height of a cone are 5 cm and 12 cm respectively. Find its slant height.
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 13 cm
The height, the radius of the base and the slant height of a cone form a right-angled triangle, with the slant height as the hypotenuse, so Pythagoras’ theorem gives \(l=\sqrt{r^{2}+h^{2}}\).
With \(r=5\) cm and \(h=12\) cm: \(l=\sqrt{5^{2}+12^{2}}=\sqrt{25+144}=\sqrt{169}=13\) cm
