4. One of the main applications of trigonometry is solving triangles. To solve a triangle means to find the
measures of all the angles and sides of the triangle.
Two ideas that come up often in applications involve the angle of elevation and the angle of
depression. In solving a triangle, at least two parts are given. The other parts can be determined by using
the definition of trigonometric functions. When solving right triangle, it is good practice to draw the right
triangle whose parts are proportional to the given data.
Label these parts to easily identify the unknowns. Then use appropriate trigonometric functions to find
the unknown parts.