9514 1404 393
Answer:
10 ft
Explanation:
The midsegment length is the average of the other two lengths.
(QR +PS)/2 = TU
QR +PS = 2×TU . . . . . . . . . . . . . . . multiply by 2
QR = 2×TU -PS = 2(14 ft) -18 ft . . . subtract PS; substitute given values
QR = 10 ft