Math question for my college algebra course

Question

Two​ vehicles, a car and a​ truck, leave an intersection at the same time. The car heads east at an average speed of 60 miles per​ hour, while the truck heads south at an average speed of 70 miles per hour. Find an expression for their distance apart d​ (in miles) at the end of t hours.

Answer 1

Since they are moving at right angles, the Pythagorean Theorem would apply. The two distances traveled by the vehicles would be

d_car = 60t and d_truck = 70t. Therefore, their distance apart at time t would be

d_separation = sqrt((60t)²+(70t)²) = sqrt(3600t²+4900t²) = sqrt(8500t²) = 10t * sqrt(85) ≅ 91.2t