The ratio of two side lengths of the triangle is given. Solve for the variable, then find the length of AB. AB:CB is 3:4 please help !

Question

anonymous · Answer

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e.mccormick · Answer

They give you a ratio and two equations.  Do you know how you would use the ratio to set up the equations equal to each other?

anonymous · Answer

x/(x-2)=3/4 simplify and find x

anonymous · Answer

i honestly dont understand what to do.... :/

anonymous · Answer

AB:BC =AB/BC
plug in values and simplify

e.mccormick · Answer

It is like saying $\cfrac{1}{2}=\cfrac{2}{4}$.  Only now you have equations in the mix.  That means you set up the equality like ArslanQureshi did, then simplify it.

anonymous · Answer

how do you set it up cuz i think tht i can do the rest if i start from there mainly cuz idk how to set stuff up but im alright with the actual math part.

anonymous · Answer

okay AB:BC means AB/BC in its simplest form see e.mccormick's post above if AB is 2 and BC is 4 then AB:BC becomes 1:2 which equals 1/2. So in questions like these write ratio as A/B and put it equal to given expressions of A and B e.g. IF A:B = 1:3 AND A=X B=2X THEN 1/3=X/2X WHICH SIMPLIFYS TO X=1 get it??

anonymous · Answer

wow yes lol thankyou!

e.mccormick · Answer

Which is where his setup comes from:$$\frac{x}{(x-2)}=\frac{3}{4}$$And why solving that will answer your question.  So start by cross multiplying and go from there.