Question 935074
Use Pythagoras' Theorem.

(a)^2+(b)^2=(c)^2
In this case you have to rearrange it to find b
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Therefore 
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(7.2)^2-(4)^2=(b)^2
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Now square root everything to find the value of b
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b=5.986651819 miles south
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b=6 miles to the nearest integer