The Minnitte family pool, PQRS, measures 48 feet by 84 feet
48 : 84 = 4 : 7
The Gaudet family pool, WXYZ, measures 40 feet by 70 feet
40 : 70 = 4 : 7
The two pools are similar
The similarity statements :
PQ/WX = QR/XY = RS/YZ = PS/WZ
Scale factor:
48/40 = 6/5
84/70 = 6/5
So
SF = 6/5