What is the dimension of the rectangle?

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2 Answers
Jan 19, 2018

Length = 10cm10cm
Width = 6cm6cm

Explanation:

Let the width of the rectangle be xx cm. Therefore, the length of the rectangle is x+4x+4 cm.

We know that, if we decrease the width by 2cm2cm and the length by 5cm5cm, the perimeter will be 18cm18cm.

That means,

2[(x-2)+(x+4-5)]=182[(x2)+(x+45)]=18

2[(x-2+x-1)]=182[(x2+x1)]=18

2(2x-3)=182(2x3)=18

2x-3=92x3=9

2x=122x=12

x=6x=6

So, the width is 6cm6cm long. Then, the length will be 6+4=10cm6+4=10cm long.

Jan 19, 2018

"dimensions are "10" cm by "6" cmdimensions are 10 cm by 6cm

Explanation:

"let the width "=wlet the width =w

"then length "=w+4larrcolor(blue)"4 more than width"then length =w+44 more than width

"decrease length by 5 "tow+4-5tow-1decrease length by 5 w+45w1

"decrease width by 2 "tow-2decrease width by 2 w2

• " perimeter "=(2xx"length")+(2xx"width") perimeter =(2×length)+(2×width)

color(white)(xxxxxxxxxx)=2(w-1)+2(w-2)×××××=2(w1)+2(w2)

color(white)(xxxxxxxxxx)=2w-2+2w-4×××××=2w2+2w4

color(white)(xxxxxxxxxx)=4w-6×××××=4w6

"now perimeter "=18now perimeter =18

rArr4w-6=184w6=18

"add 6 to both sides"add 6 to both sides

4wcancel(-6)cancel(+6)=18+6

rArr4w=24

"divide both sides by 4"

(cancel(4) w)/cancel(4)=24/4

rArrw=6

rArr"width "=6" cm "

rArr"length "=w+4=6+4=10" cm"