Section 5-4 Applying Trig Functions Objective: Students will be able to use trigonometry to find the measures of the sides of right triangles.

Example 1: If B = 42° and a = 12, find c, b, and A. You know the measure of the side adjacent the angle. The cosine function relates the side adjacent to the angle and the hypotenuse. C = A + B + C = 180 A = 180

Example 2: RECREATION A child holding on to the string of a kite gets tired and decides to put the string on the ground and secure it with a brick. The length of the string from the brick to the kite is 240 feet. A) If the angle formed by the string and the ground is °, how high is the kite? We know the angle and the hypotenuse. We want to find the height of the kite (h). h = The height of the kite is about feet.

B) What is the horizontal distance between the kite and the brick? Her we want to know the side adjacent the angle. So we will use the cosine function. 240 cos = d D = The horizontal distance between the brick and the kite is about feet.