Answer:
40
Explanation:
Going from left to right
We need to find the angle from the first triangle
The sum of the angles of a triangle is 180
80+25+x = 180
Combine like terms
105+ x = 180
Subtract 105 from each side
105-105+x = 180-105
x = 75
Then we have 3 angles that make a straight line and a straight line is 180
x + 50 + y = 180
75+ 50 + y = 180
Combine like terms
125 + y = 180
Subtract 125 from each side
125-125+y = 180-125
y = 55
We now have the triangle on the right
The angles add to 180
55+85+ ? = 180
Combine like terms
140+ ? = 180
Subtract 140 from each side
140+? - 140 = 180-140
? = 40