you'd use the pythagorean theorem.
a^2+b^2=c^2
a is the first leg, b is the second leg, and c is the third leg.
10^2+13^2=c^2
100+169=c^2
269=c^2
take the square root of both sides
16.4=c
16.4cm is your answer!
7.50 dollars because per each mile its $2.50 . and $2.50 times 3 equals $7.50
Answer:
the answer is 
Step-by-step explanation:

hope this helps :)
Try using Symbolab, I use it all the time it gives the correct answer and it gives good explanations.