Question

The sum of length,breadth and depth of a cubood is 9cm and the length of its diagonal is 11cm. Find the surface area of cuboid

Answer 1

Surface area SA = 2(lb + lh + bh)

l + b + h = 9cm

Lenth of the diognal = 11

√l² + b² + h² = 11

l ² + b² + h² = 11² = 121

(l + b + h)² = l² + b² + h² + 2(lb + lh + bh)

9² = 121 + 2(lb + lh + bh)

81 - 121 = 2(lb+lh+bh)

Surface area = -40cm²