Download Lesson 9.1 Day 2

Lesson 9.1 Right Triangle Trigonometry (Day 2)
Learning Goal: (G-SRT.C.8 - Pre-requisite Skill)
I can evaluate trigonometric functions of acute angles.
I can find unknown side lengths and angle measures of right triangles.
Essential Question: How can you find a trigonometric function
of an acute angle θ?
Homework Discussion
5 in
5 mi
8.6 km
14.1 mi
2
yd
6.
km
7.
m
8.
yd
9. yes
10. yes
11.
12.
13.
14.
no
no
yes
yes
Special Right Triangles
Know These
45°-45°-90°
1
30°-60°-90°
45°
1
60°
2
30°
45°
1
sin 45° =
=
sin 30° =
Finding an Unknown Side Length
Find the value of x for the right triangle.
Ex 1:
Ex 2:
12
60°
x
Solving a Triangle: finding the unknown side lengths and angle measures of a triangle. Use
technology.
Ex 1:
Ex 2:
Solve △ABC.
Solve △ABC.
c
a
34°
b=13
Group Consensus
1. Find the value of x for the right triangle shown.
Solve △ABC using the diagram and the given measurements.
2. B = 45°, c = 5
3. A = 32°, b = 10
4. A = 71°, c = 20
5. B = 60°, a = 7
Solving Real-Life Problems
You are hiking near a canyon. While standing
at A, you measure an angle of 90º between B
and C, as shown. You then walk to B and
measure an angle of 76° between A and C.
The distance between A and B is about 2
miles. How wide is the canyon between A
and C?
Example:
A parasailer is attached to a boat with a rope
72 feet long. The angle of elevation from the
boat to the parasailer is 28°. Estimate the
parasailer’s height above the boat.
Exit Question:
What does the standard deviation tell us about a data distribution?
Practice to Strengthen Understanding
Hmwk #32 Big Ideas p466 #21-26, 27-45 odd