So for this you will be doing proportions. Your equation will look like this: 
Firstly, cross multiply: 
Next, square root both sides of the equation, and your answer should be 
You need to use pemdas here to understand order of operations. So you need to multiply the 8 by the 4 to give 32, then add 4 to get 36. And now you can take the 32 and divide. So you get 36/32 or 9/8
Parallel lines I think, im not sure