Grade can also be defined as slope, or the ratio rise over run. The percent grade of the slope can be determined by calculating the rise over run and then multiplying by 100. The method of finding the slope relates strongly to trigonometry because of the formation of the right triangle. If the grade of something is seen as a triangle, you could use the Pythagorean theorem in order to find the rise or run. Sine, cosine, and tangent can also be used to determine the sides or angles.

I had never thought of grade describing the hills and rises that I, as a native of our beloved and ridiculously hilly Albuquerque, have gone over time and time again. I often run in my neighborhood, and I always dread the incredibly steep inclines. I can now see these hated hills as grades; I learned that one particularly brutal hill has a grade something near 20%. The number seems small, but not when I'm running up the hill like it's a flight of stairs. It is very interesting to see a way in which the trigonometry we learn in the classroom relates directly to my daily life.