Question

HELPPPP ASAPPP PLZZZZZZZZZZ

Answer 1

Use pythagorean theorem; 

a²+b²=c² where a and b are the legs and c is the hypotenuse of triangle 
5²+b²=10²
b²=100-25 
b²=75 
b=√75 
b=8.66 miles 

Hope I helped :) 

Answer 2

8.7 miles is the answer to your question