Question

The sum of the length, breadth and depth of a cuboid is 19 cm and its diagonal is 5√5 cm. Its surface area is

A. 361 cm²

B. 125 cm²

C. 236 cm²

D. 486 cm²

Answer 1

Correct option is C. 236 cm²

Given,

Sum of length ,breadth, height of cuboid = 19 cm

Diagonal of cuboid = 5√5 cm

\(=\sqrt{l^2+b^2+h^2}\) = 5√5

(Squaring both side)

= l² + b² + h² = 125......(i)

\(\therefore\)(l + b + h)² = l² + b² + h² +2(lb + bh + hl) by formula

Putting values …

= 19² = 125 + 2(lb + bh + hl)

= 2(lb + bh + hl) = 361 - 125 = 236

= surface area of cuboid = 236 cm²