Answer:
1/2
Step-by-step explanation:
y = 1/2x - 1/3
This is written in the form y = mx+b where m is the slope and b is the y intercept.
The slope is 1/2 and the y intercept is -1/3
We can use the vertical angle theorem which states that any two opposite angles are congruent. So, you can just set the two measures equal to each other and solve for x:




So, your answer is
20°.
It should always have the same perimeter if it stays the same geometric figure.