From a point P, R is 5km due west and 12km due south. Find the distance between P and R

A.
5km 
B.
12km 
C.
13km 
D.
17km
Correct Answer: Option C
Explanation
Using Pythagoras theorem
(PR^2=PO^2+OR^2\
PR^2=5^2+12^2\
PR=sqrt{25+144}=sqrt{169}=13km)