Natalie S. answered 09/30/21
Experience Math Educator Helping Students Build Confidence
Hi Shireen,
The two vertical lines in this problem are parallel, as indicated in the diagram. If you turn your head sideways, you'll see that there is an F pattern (corresponding angles), so that means that:
(5x) + (3x + 9) = (9x - 3)
(I used parentheses above just so that you can see which angles I'm referring to.)
I'll rewrite it as:
5x + 3x + 9 = 9x - 3
If we go ahead and solve this for x, we get:
8x + 9 = 9x - 3
12 = x
Go ahead and substitute x = 12 in to the expression 3x + 9.
This will give you: 3(12) + 9 = 36 + 9
= 45 degrees
Since angle 2 and (3x+9) are vertical angles, they are congruent. That means that angle 2 also measures 45 degrees.
I hope this helps!