Find the missing length in the similar triangles

Question

Find the missing length in the similar triangles.

not sure how to write this since i cant draw the two triangles. 

 

One Triangle has the number 82 on the top, the bottom has number 80 and the last have an x on the side.

Second triangle has the number 41 on the top, on the bottom is number 40, and the side is number 9

 

 

 

 

 

 

( answer is x=18, but i need help step by step on how they got this answer) 

Answer 1

If you have similar triangles that means that the sides are proportional or when you divide the sides you will get the same number for them all

 

so you have 82 and 41, if you do 82/41 that equals 2

same with 80 and 40, 80/40 is 2

so the last needs to follow the same rule ?/9 = 2