If the car has maintained a constant speed of 64 mi/h, how far is it from its starting position? (read description)

Question

A car travels along a straight road, heading east for 1 h, then traveling for 30 min on another road that leads northeast. If the car has maintained a constant speed of 64 mi/h, how far is it from its starting position? (Round your answer to one decimal place.) 

Answer 1

Draw and label a diagram

Use Law of Cosines

d² = 64² + 32² - (2))(64)(32) cos 135^°