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I'm struggling with this question...

The sides of a rectangle are in the ratio 2:3. The diagonal is of length 26cm. Find the perimeter.

Thanks :smile:
Let x be the length of the short side.

What is the perimeter in terms of x ?
Reply 2
Avatar for lerjj
lerjj
13
Original post by Junimeg
I'm struggling with this question...

The sides of a rectangle are in the ratio 2:3. The diagonal is of length 26cm. Find the perimeter.

Thanks :smile:


label the sides 2a and 3a. Go from there.

Edit: ninja'd
Reply 3
Avatar for Junimeg
Junimeg
OP
2
Thanks, but I still can't do it :L Could someone walk me through it please?
Original post by Junimeg
Thanks, but I still can't do it :L Could someone walk me through it please?


use Pythagoras
Reply 5
Avatar for Celinexxx
Celinexxx
split the rectangle in half using the diagonal to make 2 right angled triangles.
The hypotenuse/diagonal is 26 cm. the short side is 2x and the long side is 3x
Using pythag. 26^2=(2x)^2+(3x)^2
676 = 4x^2 + 9x^2
676 = 13x^2
52 = x^2
x = 7.2...
Then the perimeter will be 2x+2x+3x+3x = 10x
Therefore the perimeter = 72 cm
Reply 6
Avatar for davros
davros
16
Original post by Celinexxx
split the rectangle in half using the diagonal to make 2 right angled triangles.


Please don't post full solutions - it's against forum rules! :smile:

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