The volume of a cuboid is 54cm3. If the length, width and height of the cuboid are in the ratio 2:1:1 respectively, find its total surface area
-
A.
108cm2 -
B.
90cm2 -
C.
80cm2 -
D.
72cm2
Correct Answer: Option B
Explanation
V = L x B x H
V = (2x times x times x = 2x^3)
= 54cm3
i.e. 2×3 = 54
x3 = (frac{54}{2}) = 27
x = 3(sqrt{27})
x = 3
L = 2x i.e. 2 x 3 = 6cm
B = x i.e. x = 3cm
H = x i.e. x = 3cm
but A = 2(LB + LH + BH) = 2(6 x 3) + (6 x 3) + (3 x 3) = 2(18 + 18 + 9) = 2(45)
= 90cm2