Need with 1-6 it has to do with triangle mid segment theorem only answer if right because this depend on my grade

Problem 1)

x = 9

x is a midsegment of the triangle so it is half of the parallel side (18)
half of 18 is 9
18/2 = 9



Problem 2)

x = 5

In reverse of problem 1, we double the value 2.5 to get 5
The segment 2.5 units long is half that of the side x



Problem 3)

x = 11

Similar to problem 1, we divide 22 in half to get 11



Problem 4) 

y = 35

The two triangles are similar. Therefore, they have congruent corresponding angles. The 35 degree angle and the y degree angle are corresponding angles that are congruent (due to the parallel horizontal lines)



Problem 5) 

y = 90

This is similar to problem 4. The 90 degree angle (marked by the square box symbol) and the y degree angle are congruent. They are corresponding angles. We have two similar triangles. 



Problem 6) 

y = 50

As you can probably guess by now, problem 6 is similar to problems 4 and 5. The 50 degree angle and the y degree angle are congruent corresponding angles. So that's why y = 50.