find the missing side measurement marked x given that the two triangles are proportional. x=

Answer 1

You did not give the specific lengths of the sides, so I will have to give you a general answer. You can substitute in the the specific values from your problem.

Say the first triangle has sides of lengths a, b, and c. Say the second triangle has sides of lengths d, e, and f.

Be very careful to figure out which sides of the first triangle are proportional to what sides of the second triangle. This is the trickiest part. Proportional triangles have corresponding angles that are not just proportional they are equal to each other. This can help you figure out the corresponding sides. I like to sketch the second triangle so that it is oriented in the same way as the first triangle. This helps me set up my proportion.

If a is proportional to f, b is proportional to d, and c is proportional to e, then you can set up a proportion like this:

a b c

____ = _____ = ______

f d e

Say that you need to solve for a and that you have f, b, and d. Then, you solve the below proportion for a:

a b

____ = _____

f d

I'll make up some values for f, b, and d and fill them into the proportion and then solve by cross-multiplication.

a 5

____ = _____

12 15

15a = 60

15a 60

___ = ____

15 15

a = 4