Do complementary angles form straight angles?

no

Explanation: Complementary angles form a right angle (L shape) and have a sum of 90 degrees.

Angles 1 and 4 are alternate angles and thus have the same measurement. You will set their equations equal to each other and solve for the variable. 

6n + 1 = 4n + 19

Subtract 1 and 4n from both sides to get variables on one side and constants on the other. 

6n - 4n = 19 - 1

Combine like terms and solve for n.

2n = 18
n = 18 / 2
n = 9

Angles 1 and 2 are congruent as labeled in the graph. 

So angle 2 is also 6n + 1

Plug in for 9 for n

6(9) + 1
54 + 1
55

Option C is your answer.