The sum of the length, the breadth and the height of a cuboid is 18 cm. If the length of its diagonal is 13 cm. then the total surface area of the cuboid is:
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 155 cm2
Given:
L + B + H = 18
L2 + B2 + H2 = D2 = 132
Formula used:
(a + b + c)2 = a2 + b2 + c2 + 2(ab + bc + ca) ---- (1)
Total surface area of a cuboid = 2(LB + BH + HL)
Where, L = length, B = breadth and H = height
Calculations:
Using equation (1), we get
⇒ 182 = 132 + 2(LB + BH + HL)
⇒ 2(LB + BH + HL) = 324 - 169
⇒ 2(LB + BH + HL) = 155 cm2