To make one serving you need 3cups/8servings = 3/8 cup.
To make 6 servings you need 3/8cup * 6 servings = 9/4 cups = 2.25 cups.
Assuming you want to find x?
You know that the angles at C and B have to be the same (6x) because it’s an isosceles triangle (as indicated by the lines going through AC and AB), and angles in a triangle add to 180*
So 3x + 6x + 6x = 180*
15x = 180*
x = 180*/15
x = 12*
