How to find value of x when given the length, width and total surface area Example - Diagram screenshot above:

Total Surface Area of cuboid: 2lb + 2bh + 2hl

Length: 10cm
Base: 2cm
Height: xcm

Simplify:
2(10)(2) + 2(2)(x) + 2(x)(10) = 112

40 + 4x + 20x = 112
40 + 24x = 112

Make x the subject, therefore subtract 40 on both sides.

24x = 112 - 40
24x = 72

Find the value of x, hence divide by 24 on both sides.

x = 72/24

x = 3