8.3 Solving Right Triangles
Trigonometry Part 2: Finding Missing Angles
Part 1: 8.2 Warm Up!

Part 2: Identifying Angles
15
8
sin A =
8
17
cos A =
15
17
tan A =
sin A =
15
17
cos A =
8
17
tan A =
8
15
Part 3: Finding Missing Angles
How do you find a missing angle?
Inverse Trigonometric Functions
If sinA = #, then
If cosA = #, then
If tanA = #, then
2
3
101
90
A
7
x
19
x
B
C
Let’s put it all together! Using given measures to find the unknown angle measures or side lengths of a
triangle is known as ___________________________________________. To solve a right triangle, you
need to know one side length and an acute angle measure or _________________________________.
To solve for a side: _______________________________
To solve for an angle: _____________________________
Solve the Right Triangle: Find the unknown measures. Round the side
lengths to the nearest hundredth and angle measures to the nearest degree.
12)
13)
14) The coordinates of the vertices of ∆PQR are
P (–3, 3), Q (2, 3), and R (–3, –4).
15) A highway sign warns that a section of road ahead has a 7% grade.
To the nearest degree, what angle does the road make with a horizontal line?