Answer
Angle A = 40 degrees
Angle B = 80 degrees
Measure BCF = 120 degrees
Measure EFD = 60 degrees
Explanation:
Angle A:
Ok, so we know angle A is congruent to angle D because of the line. If you make an equation out of it, you get 2x+20 = 3x+10. If you solve this equation:
2x + 20 = 3x + 10
20 = x+10
10 = x
you will get x=10. Plug it into the equation, and Angle A = 40 degrees.
Angle B:
The two lines that are both on angle B and E mean that they are congruent. We know that angle E = 80 degrees, so angle B does too.
Measure BCF:
We know that Angle A = 40 degrees, and angle B = 80 degrees. The degree sum of all angles in a triangle is 180 degrees.
80 + 40 = 120
180 - 120 = 60
So measure BCA = 60 degrees.
That angle is on a straight line. Two angles on a straight line add up to 180 degrees.
180 - 60 = 120.
So, Measure BCF = 120 degrees.
Measure EFD:
We already found measure BCA while finding measure BCF, and that is just congruent to EFD.
So, measure EFD = 60 degrees