Answer:
Ok, I'll give this a shot even if I'm in 6th grade
Step-by-step explanation:
So, triangles are always 180 degrees in total, right?
One side is 31, and there is something on the edge indicating a 90 degree angle (right angle).
You can subtract both of these from 180, try! If you just want some of my thinking:
180-(31+90)=51
15x-1, so you must find what makes 52 because 52-1=51.
(sorry if this is a bit confusing)
Hope it helps, I'm only in 6th grade, this one took a little to solve!
