Anonymous
Anonymous asked in Education & ReferenceHomework Help · 2 years ago

Finding dimensions of a rectangle?

The length of a rectangle is four times it’s width.

If the perimeter of a rectangle is 90cm

What is length and width

Can someone please help me

5 Answers

Relevance
  • 2 years ago

    The perimeter of two of the sides, the length and the width, is 45cm.

    We can divide this by five (4+1, because four of the width is the same as one of the length), and find the length.

    We then multiply the length by 4 to get the width.

    Width- 36cm

    Length- 9cm.

  • 2 years ago

    P = 2(l + w)

    But l = 4w

    Substitute

    P = 2(4w + w)

    P = 2(5w)

    P = 10w

    90 = 10w

    w = 9

    Hence

    l = 4 x 9 = 36

  • 2 years ago

    (l+b)*2=90

    (4*b+b)*2=90

    5b=45

    b=9

  • 2 years ago

    Let x = the width

    Then 4x is the length

    The perimeter is than 2x + 8x or 10X

    10x = 90 cm, so x = 9 cm. You can do the rest, at least I hope you can.

    Algebra requires you to show all your work so I have done so.

  • How do you think about the answers? You can sign in to vote the answer.
  • 2 years ago

    Let's use w for the width. The length is 4w.

    So what is the perimeter of a rectangle? It's two times its width plus two times its length, right? So 2*w+2*4w, which is 2w+8w, which is 10w. So whatever the perimeter of the rectangle is, the width is 1/10 of it and the length is 4/10 of it.

Still have questions? Get your answers by asking now.