Runners in a long distance race start out going 8 kilometers east and then head north for the remainder of the race. The finish line is 10 kilometers from the starting line. How far did the runners travel north?

A. 2 km

B. 6 km

C. 10 km

As we project the following problem, we can see that the runner is forming a triangle when we try to connect the final stop and the initial stop of the runners. In this case, the resultant is 10 kilometers and the x-axis component is 8 km, that is the y-component should be square root of 100-64 equal to B. 6 km