We found the factors and prime factorization of 80 and 100. The biggest common factor number is the GCF number. So the greatest common factor 80 and 100 is 20
The top angle is 50 because 180 - 130 = 50 Since the top angle is 50, the two bottom angles have to add up to 130. Since the bottom angles are the same, you can do 130 / 2 to find the angles which equals 65.