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## Homework Statement

A passenger train is approaching a railway crossing from 105m to the east, at 54km/h. Meanwhile a train approaches from 140m to the north, at 72km/h. How fast is the distance between them changing after 5 seconds?

## Homework Equations

Pythagorean Theorem?

## The Attempt at a Solution

It looks to me that there are four constants in this question, namely:

The distance and velocity of the train which are 140m and 72km/h respectively.

The distance and velocity of the car which are 105m and 54km/h respectively.

I drew a right angled triangle and labeled x the car distance on the horizontal and y the train distance on the vertical with z marked on the hypotenuse.

I guess before i go further, i need to know if i am setting up this problem right first, because i am confused as to how to setup all the given data. Help?