I wish I could help but I can’t see the it
7/10 of 80 is 56
4/5 of 80 is 64
3/4 of 80 is 60
5/8 of 80 is 50
1/2 of 80 is 40
1/4 of 80 is 20
1/10 of 80 is 8
1/8 of 80 is 10
to work these out divide the number by the denominator (bottom number) and multiply by the numerator (top number)
Since it's isosceles, ∠ABC = (180-30) / 2 = 75
25% is your answer........