Find the value of l in the frustrum above

Find the value of l in the frustrum above

Correct Answer: Option A

Explanation

ΔABE and ΔACD are similar

∴	x	= 3 6
	x+4

6x = 3(x+4)
6x = 3x + 12
3x = 12
x = 4
In ΔACD; L² = (4+4)² + 6²
= 8² + 6²
= 64 + 36
= 100L =
√ 100 
= 10cm
In ABE, AE² = 4² + 3²
= 16 + 9
= 25
AE = 5cm
∴L = 10 – 5
= 5cm