In the figure, PQRS is a rectangle. If the shaded area is 72 sq. cm, find h.
Attached Figure / Diagram
A
12cm
B
10cm
C
8cm
D
5cm
Verified Correct Answer: D.
Step-by-Step Mathematical Solution
From the diagram, PQRS is a rectangle
Area of shaded part = 72sq.cm
But 72 = 3h - 4 + 6h - 4 + 4h
= 72 - 16h - 8
= 16h - 72 + 8
=16h = 80
h = \(\frac{80}{16}\)
= 5cm
Source: WAEC / JAMB / NECO Classroom Archive (Record #54911)