When a jogger runs south and then turns west, we have right angle between segment 0.8 mi and segment to the west. So it is legs of the right triangle.
1.7 mi is hypotenuse.
hypotenuse² =(leg1)²+(leg2)²
1.7²=0.8² + (leg2)²
(leg2)²=1.7²-0.8² = 2.25 mi²
leg2=√(2.25 mi²)
leg2=1.5 mi
Answer is 1.5 mi.
