Question

If the radius of the cone is 5 cm and its perpendicular height is 12 cm, then the slant height is ______.

Options

• 17 cm

• 4 cm

• 13 cm

• 60 cm

Answer 1

If the radius of the cone is 5 cm and its perpendicular height is 12 cm, then the slant height is 13 cm.

Explanation:

r = 5 cm (radius)

h = 12 cm (perpendicular height)

l = ? (slant height)

The slant height (l) of a cone is found using the Pythagorean theorem:

l² = r² + h²

l² = 5² + 12²

l² = 25 + 144

l² = 169

l = `sqrt169`

l = 13 cm