Final answer:
The shortest straight path back to the starting line is 5 miles.
Step-by-step explanation:
To determine the shortest straight path back to the starting line, we can represent the runners' movements on a coordinate plane. Start by assigning the starting point as the origin (0,0). The first leg of the journey is 3 miles north, so the coordinates for that point are (0,3). The second leg is 5 miles west, so the coordinates for that point are (-5,3). To determine the shortest path back to the origin, we can use the distance formula, which is based on the Pythagorean Theorem. The distance formula is:
d = √((x2-x1)2 + (y2-y1)2)
Using the coordinates (0,3) and (-5,3), we can substitute those values into the formula:
d = √((0-(-5))2 + (3-3)2) = √(52 + 0) = √25 = 5 miles
Therefore, the shortest straight path the runners must run to get back to the starting line is 5 miles.
Learn more about Pythagorean Theorem and the Coordinate Plane