Answer: x = 3
Step-by-step explanation:
If 3x is the midsegment of the triangle, then it is half the length of the base, which implies that the length of the base equals twice the length of the midsegment:
base = 2 * midsegment
18 = 2 (3x)
18 = 6x
÷6 ÷6
3 = x
