Ahelicopter rose vertically 300m and then flew west 400m. how far was the helicopter from it's starting point?

You can solve this in two easy ways. First off we'll do it mathematically, using what's called the Pythagorean Theorem. This is as follows (only for right triangles!): a^2+b^2=c^2
in this equation, a and b are the two sides, or legs, of the triangle that form a right (90 degree) angle, and c is the other, diagonal side, aka the hypotenuse.
For your question, a and b (the two sides of the triangle) are 300 and 400m. using the theorem i put above,
300^2+400^2=c^2 (you want to find c, as that is how far the helicpoter is from the start)
250000=c^2
c=500m
and there's your answer
the other, much easier way is to know the fact that one example of a right triangle, aka a "Pythagorean triple", has sides of 3 and 4 and a hypotenuse of 5. Knowing that, one could solve your question in a matter of seconds.
so there you go. 500m

I'm just guessing here, but I think it can be solved using the Pythagorean Theorem. So, we know a and b, so 300^2 (a) + 400^2 (b) = c^2. So, 90000 + 160000 is 250000. 250000 squared is 500. So, I believe the answer is 500m west of the original starting point.