<PRE><B>Question 785596</B>
Two cars leave an intersection. One car travels north; the other east.
 When the car traveling north had gone 9 mi, the distance between the cars was 3 mi more than the distance traveled by the car heading east.
 How far had the east bound car traveled?
:
Let e = distance traveled by the eastbound car
then
(e+3) = distance between e and northbound car after it travels 9 mi
:
This is a pythag problem, a^2 + b^2 = c^2, where
a = 9
b = e
c = (e+3)
:
9^2 + e^2 = (e+3)^2
81 + e^2 = e^2 + 6e + 9
Subtract e^2 from both sides
81 = 6e + 9
81 - 9 = 6e
72 = 6e
e = 72/6
e = 12 mi traveled by the east car when they were 12+3 = 15 mi apart
:
:
Check using your calc, enter
{{{sqrt(9^2 + 12^2)}}} results: 15</PRE>