Answer: The answer is x = 9.
Explanation:
You can answer this question with a proportion. This is the proportion I used:
6/x = 10/15
Basically, the sides labeled with 6 and 10 are corresponding sides. If you straighten the triangles up, the 6 is at the bottom, or the base, and so is the 10. If x is in the position it is, you have to find the side and measurement for that side that corresponds to x. In this case, that measurement is 15. Now that you have the proportion, just cross-multiply and divide.
6 times 15 = 90
90 divided by 10 = 9
So, there is your answer. X is equal to 9.