A cone has a radius of 9 cm and a slant height of 15 cm. If the height of the cone is increased by 50%, what will be the new slant height?
Show answer & explanation
Correct answer: A
Explanation
Has been given :
radius = 9 cm
Slant height = 15 cm
According to the formula:
l² = r² + h²
15² = 9² + h²
225 = 81 + h²
h² = 144
h = 12 cm
New height= 12 + 50% of 12= 12 + 6= 18 cm
new slant height
l = √(9² + 18²)
= √(81 + 324)
= √405
= 9√5
=20.12 cm