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The perimeter of a rectangle is 280cm. The ratio of the width to the length is 3:4. What is the length of the rectangle?

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Answer:

So first we need to get the perimeter formula. P = 2(w+l). We know P but we dont know w and h.

280/2 = 140. So now we know that 140 = w+l. We also know that the length is 4/3 times greater than the width (we used the ratio). To prove this 3*4/3 = 4, just like in ratio. So we have 2 equations

140 = w+l

l = 4/3w

Now we can plug into 140

140 = w+4/3w

So if you solve algebraicly you get

60 = w.

Now we can find that the length =

80 is the answer to length..

Now to prove answer 60+80 = 140.

So the answer is

Width: 60

Length: 80

brainliest?

The length of the rectangle is 80cm and the width is 60cm

The perimeter of the rectangle is given as 280cm and the ratio of the length to width is 3:4.

The formula of perimeter of rectangle is given as;

[tex]P=2(L+W)[/tex]

This implies that

[tex]280=2(l + w)\\280=2l+2w\\l+w=140...equation(i)[/tex]

Length

But let's go back to our given ratio

3:4 = l:w

3l = 4w

make w the subject of formula

[tex]w = (3/4)l[/tex]

Let's substitute this into equation (i)

[tex]l+w=140\\w=(3/4)l\\l+(3/4)l=140\\(7/4)l=140[/tex]

solve for l

[tex]\frac{7}{4}l=140\\4*140 = 7l\\560=7l\\l= 560/7\\l=80[/tex]

Width

Since L = 80, let's substitute it into equation (i)

[tex]l+w = 140\\80+w = 140\\w = 140 - 80\\w = 60[/tex]

From the calculations above, we have the following data

  • length = 80cm
  • width = 60cm
  • perimeter = 280cm

The length of the rectangle is 80cm and the width is 60cm

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