Question 19037
first, find how far each plane travelled...
150 mph * 2 hours = 300 miles
200 mph * 2 hours = 400 miles

since one is traveling north and the other is travelling west, and you want to find the distance between them, look at it as a right triangle.  If you do not understand why it is a triangle, draw it out on graph paper (make 1 square equal to 100 miles) where the airport is  the origin, plane one is 3 squares up and plane 2 is 4 squares over.

Pythagorean theorum says {{{a^2+b^2=c^2}}} where c is the hypotenuse; a =300; b=400

Therefore, {{{300^2+400^2=c^2}}}

calculating the exponents out leaves {{{90,000+160,000=c^2}}}

therefore, {{{250,000=c^2}}} {{{sqrt(250,000)=c=500}}}

at 3pm, the planes will be 500 miles apart