Correct Answer - Option 2 : 54 cm

^{2}
**Given:**

Perimeter of upper circular end of frustum = 20 cm

Perimeter of lower circular end of frustum = 16 cm

Slant height (l) of frustum = 3 cm

**Formula used:**

Curved surface area of frustum = π(r_{1} + r_{2})l

Where, r_{1} = Radius of upper base of frustum

r_{2} = Radius of lower base of frustum

Perimeter of circle = 2

πr

**Calculation:**

Perimeter of upper circular end of frustum = 20 cm

⇒ 2πr_{1}_{ }= 20

⇒ r1 = 10/π

Again,

Perimeter of lower circular end of frustum = 16 cm

⇒ 2πr_{2} = 16

⇒ r_{2} = 8/π

According to the question:

Curved surface area of frustum = π(r1 + r2)l

⇒ 3π (10/π + 8/π)

⇒ 3 × (18/π) × π

⇒ 3 × 18 = 54

**∴ The curved surface area of the frustum is 54 cm**^{2}.