To find the solution, simply take 3 and divide it by 12. 3/12 as a fraction would be simplified down to 1/4 or 0.25. Therefore, each student would receive one quarter of a pizza.
In a triangle the midline joining the midpoints of two sides is parallel to the third side and half as long ⇒
2(3x + 2) = 2x + 20
6x + 4 = 2x + 20
6x - 2x = 20 - 4
4x = 16
x = 16/4
x = 4
midsegment = 3x + 2 = 3*4 + 2 = 12 + 2 = 14
2 times 108 is 216
3 times 72 is 216
4 times 54 is 216
6 times 36 is 216