Question 338490
If you make yourself a diagram, you'll notice that the distances represented by the car's travels are the sides of a right triangle...their distance at any time can be found using the Pythagorean Theorem.

Now remember, rate times time equals ditance...

After .5 hours, the north side is 25 km, and the east side is 35 km.

Now apply a^2 + b^2 = c^2 and find c.
We get c^2 = 25^ + 35^2 = 625 + 1225 = 1850
c = sqrt(1850) = about 43 km

Now repeat the procedure for two hours travel...see if you get c = 172 km...