Question

Professor plum is standing 10 feet from a street lamp the light from the lamp is making his shadow 8 feet long. he estimates that the angle of elevation from the tip of his shadow to the top of the street lamp is 40 degrees. about how high is the street lamp?
I know it's 18tan40, but where did the tangent come from? How do you know it's tan?

Answer 1

Tangent uses the values opposite (the way the angle faces) and adjacent (the values next to it). Basically, on a triangle, tangent uses the lengths of the two sides that are NOT the hypotenuse.