A problem I should be able to solve (geometry)

[silenzer]

A problem I should be able to solve :( (geometry)

This is a random problem I discovered on the internet:

If the area of a rectangle is diminished by 36%, what are the sides of the original rectangle if the sides of the diminished one are 36mm and 48mm?

My answer: Let a and b be the original sides (not diminished).

ab*0,64=1728, so ab=2700. We know that c/d = 36/48 = a/b = 3/4 so a = 3/4 b

Now: 3/4 b*b = 2700
So b^2 = 3600
And then b = +- sqrt of 3600, but since we want distance the answer is b=60.

Because a = 3/4 b, we get a = 3/4 * 60 = 45.

 

[OldEngr63]

Where did the 1728 come from?

Did you check your final answers? Doo they work?

 

[tal444]

Where did the 1728 come from?

From multiplying 36 by 48 to get the area. And your answer looks correct silenzer.

 

[silenzer]

Okay, thanks. I saw a different answer elsewhere and therefore thought I was wrong. Thanks for the help.