Question by Summer Clouds - Discuss with MathYouLike

Summer Clouds moderators

28/11/2017 at 10:21

The figure shows rectangle PQRS composed of three congruent rectangles. If the area of PQRS is 1536 cm\(^2\), what is its perimeter?
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Phan Thanh Tinh Coordinator 28/11/2017 at 12:23

Let a (cm) be the width of the small rectangles, then 2a is their length and the perimeter of the rectangle PQRS is : 2(2a + a + 2a) = 10a

The area of each small rectangle is : 1536 : 3 = 512 (cm²)

We have : \(2a.a=512\Leftrightarrow a^2=256\Leftrightarrow a=16\)

The answer is : 16 x 10 = 160 (cm)
Vũ Mạnh Hùng 02/12/2017 at 20:53

The answer is :160(cm)

It is correct?
KEITA FC 8C 28/11/2017 at 21:52

Let a (cm) be the width of the small rectangles, then 2a is their length and the perimeter of the rectangle PQRS is : 2(2a + a + 2a) = 10a

The area of each small rectangle is : 1536 : 3 = 512 (cm2)

We have : 2a.a=512⇔a2=256⇔a=162a.a=512⇔a2=256⇔a=16

The answer is : 16 x 10 = 160 (cm)

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