two cars start moving from the same point One travels south

two cars start moving from the same point. One travels south at 100 km/hr and the other travels west at 50 km/hr. How far apart are they two hours later?

Draw the picture.
The southbound car has gone 200 km in 2 hrs
The westbound are has gone 100 km in 2 hrs
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Using Pythagoras to find the distance beween them you get:
d = sqrt(100^2+50^2)
d = sqrt(10000+2500)
d = 320.156 km