Right Triangle Trig

1
Right Triangle Trig

• Section 4.8

2
Learning Goal

• To solve right triangles

3
A Generic Triangle
B
ß
c
a
a
?
A
C
b
4
Solve for the missing parts.
5
Angle of depression
The altimeter of a jet approaching OHare Airport
in Chicago reads 5900 ft as it passes directly
over the Sears Tower. At the same time, the
angle of depression from the plane to the end of
the runway is 5º. How far is it from the base of
the Sears Tower to the end of the runway?
5900 ft
x
6
Angle of elevation
At 10 AM on April 26, 1998, a radio tower 300 ft
high casts a shadow 50 ft long. What is the
angle of elevation of the sun to the nearest
degree?
7
Bearings and Navigation

• A bearing measures the acute angle a path or line
  of sight makes with a fixed north-south line
  like in the picture below. For example, the
  bearing of S 35o E in the figure on the left
  means 35 degrees east of south.

80o
35o
8
Bearing and Navigation

• A ship leaves port at noon and heads due west at
  20 knots, or 20 nautical miles (nm) per hour. At
  2pm, the ship changes course to N 54o W. Find
  the ships bearing and distance from the port of
  departure at 3pm.

c
9
What did I learn today?
10
Homework

• P. 326 328 (17 39 odds)