I hope this helps you
2x+7=3x-7
x=14
2x+7+12y+1=180
2.14+8+12y=180
12y=180-36
12y=144
y=12
15 because 3 is one serving and multiplied by 5 servings is 25
You have to turn angle abe to the right twice in order for it to be symmetrical to angle gfe .
A = 12.5
2/5 = 0.4
5/0.4 = a