Answer: 85 m
Explanation:
Refer to the diagram below.
you walked from A to B (due North) 30 km. Then turned left and moved from B to C (due west) 80 km.
To find out how far are you from the starting point, we need to calculate distance AC.
Consider the right-angles triangle ABC. Then,
AC²= AB²+BC²
⇒AC = √(30 km)²+ (80 km)²
⇒AC = 85 km (approx)
Thus, you are originally 85 km away from your home.