Answer:
x = 45
Explanation:
A straight line always equals 180. The have that 180 angle split in two in the diagram. One equals 45 degrees and the other is 3x. You need to know x. So first you must find what 3 and x together is. To do that, we start with our given knowledge. 180 degrees and 45 degrees. 45 degrees and 3x must equal 180 when added together. Therefore, we can do 180 - 45 to figure out what 3 and x together is. We end up with 135 degrees. Now we have this 3x = 135. We need to isolate x. So we divide by 3. 135 divided by 3 is 45. That is our answer. x = 45 degrees.
I hope this helps :)