Question 309928: Use a proportion to find the unknown length in the pair of similar figures.
These both sahpes are triangles.
Figure A. Figure B.
CB= 144cm IH= 108cm
AC= 24cm GH= 126cm
AB= 168cm GI= _______
Please before 10:00 pm
I will be dead if i do not hand this sheet in tomorrow.
Thanks
Answer by toidayma(44)   (Show Source):
You can put this solution on YOUR website! Well, first, you have to figure out which sides of the triangle ABC is proportional to which side of the triangle GHI.
Because two triangles are similar, we must have something like a/g = b/h (a,b are sides of ABC; g,h are sides of GHI), this leads to a/b = g/h.
Since we already know the length of two sides of triangle GHI, we will use this proportion to determine which two sides of ABC is proportional to IH and GH.
This means: IH/GH is equal to a ABC's side/another ABC's side.
IH/GH = 108/126 = 6/7.
Which two sides of ABC has this proportion?
AC/BC = 24/124, too small, this cant not equal to 6/7
AC/AB = 24/168, too small, this cant not equal to 6/7
BC/AB = 144/168 = 6/7. Bingo! So BC/AB = IH/GH or BC/IH = AB/GH = 124/108 = 31/27.
This proportion must also be equal to AC/GI, which means 24/GI = 31/27 or GI = 24*27/31 = 648/21 ~ 20.9(length unit).
Is it clear?
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