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Step-by-step explanation:
area ofQXRY = area of PQRS- area of PXYS
= 84 - 21
area of QXRY = 63 cm²
Now
In
QXRY
area of rectangle = l×b
= 9cm × a
or, 63 =9a
so, a = 7 cm
Now
for PXYS
Area of rectangle = l×b
21 = a×b
because QR = PS = a cm (opposite sides of rectanhle are equal)
or, 21=7b
so, b = 3cm
so,
a= 7cm
b= 3cm