Question

8. The perimeter of a rectangular board is 70 cm.
Taking its length as x cm, find its width in terms of x.
If the area of the rectangular board is 300 cm2
find its dimensions.​

Answer 1

Answer:

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Step-by-step explanation:

Perimeter of the rectangle=70cm

Length of the rectangle=xcm

We know,

Perimeter of the rectangle=2(length+breadth)

=>70=2(x+breadth)

=>

2

70

=x+breadth

=>x+breadth=35

=>breadth=35−x

Given,area of rectangular board=30cm

2

=>length+breadth=300

=>x(35−x)=300

=>−x

2

+35x−300=0

=>x

2

−35x+300=0

=>x

2

−20x−15x+300=0

=>x(x−20)−15(x−20)=0

=>(x−20)(x−15)=0

∴x−20=0 or x−15=0

=>x=20 or x=15

∴35−x=35−20 or ∴35−x=35−15

=15 or =20

∴Dimensions are 15 and 20cm

Answer 2

Step-by-step explanation:

the length and breath is 17.5