Respuesta :

Given:

PQRS is a rectangle and XY is parallel to PS.

RY = 9 cm, QR = a cm and YS = b cm

Area of PQRS = 84 cm²

Area of PXYS = 21 cm²

To find:

The value of a and b.

Solution:

RS = 9 + b

Area of rectangle = length × width

Area of PQRS = QR × RY

QR × RS = 84

[tex]a \times (9 + b) = 84[/tex]

[tex]9a+ab=84[/tex] ----------- (1)

Area of PXYS = XY × PS

XY × PS = 21

[tex]a\times b=21[/tex] (since QR = XY)

[tex]ab=21[/tex] ----------- (2)

Substitute (2) in (1).

[tex]9a+21=84[/tex]

Subtract 21 from both sides, we get

[tex]9a = 63[/tex]

Divide by 9 on both sides, we get

a = 7

Substitute a = 7 in (2).

[tex]7 b=21[/tex]

Divide by 7 on both sides, we get

b = 3

The value of a is 7 cm and b is 3 cm.