Answer:
The answer is below
Explanation:
PQRS is a rectangle. The length of rectangle PQRS = 9 cm + b cm = (9 + b)cm
The breadth of PQRS = a. Hence:
Area of PQRS = length * breadth = (9 + b)(a) = 9a + ab
but Area of PQRS = 84 cm²
9a + ab = 84 (1)
In rectangle PXYS, length = QR = a cm, breadth = YS = b cm
Hence area of PXYS = length * breadth = (a)(b) = ab
But Area of PXYS = 21 cm²
ab = 21 (2)
substitute ab = 21 in equation 1:
9a + 21 = 84
9a = 84 - 21
9a = 63
a = 7 cm
ab = 21
7b = 21
b = 3 cm
Therefore a = 7cm, b = 3 cm