Question

The total surface area of frustum cone is 2,700 $m^2$. The diameter of a top cone is 3 and the bottom cone is 4 m. What is the curved surface area of a frustum cone? (Use $\pi$ = 3).

• A. 2,681.25 m
• B. 2,300.23 mm
• C. 2,120.25 cm
• D. 2,300.12 m

Answer 1

The correct option is A 2,681.25 m

Total surface area = $\pi (R+r)s+\pi R^2+\pi r^2$

Curved surface area = $\pi$(R + r)s

Diameter = radius $\times 2$

Radius, R = 2 m, r = 1.5 m

Therefore, 2,700 = Curved surface area $+\pi (2^2+{1.5}^2)$

2,700 = Curved surface area $+3\times (4+2.25)$

$2,700-18.75=$Curved surface area

Curved surface area = 2,681.25 $m^2$