Accelerated
Coordinate
Algebra/Analytic
Geometry A
Unit 8: Right Triangle
Trigonometry
Excerpts from Georgia Department of
Education Webinar November 15, 2012
melissa.stewart@hallco.org
November 2012
Warm-Up
If four circles are placed around a central circle with diameter of 6
cm, as pictured below, what is the radius length of each of the
outer circles?
melissa.stewart@hallco.org
November 2012
What’s the main idea of Unit 8?
• Using similar triangles to develop
understanding of trigonometric ratios.
• Determine that trigonometric ratios can be
used to solve application problems involving
right triangles.
Concepts & Skills to Maintain from Previous Grades

number sense

computation with whole numbers, integers and irrational numbers, including
application of order of operations

operations with algebraic expressions

simplification of radicals

basic geometric constructions

properties of parallel and perpendicular lines

applications of Pythagorean Theorem
melissa.stewart@hallco.org
November 2012
Websites to help with the above:
-
Review of right triangles and Pythagorean Theorem:
http://real.doe.k12.ga.us/content/math/destination_math/MSC5/msc5
/msc5/msc5/MSC5/Module3/Unit1/Session1/Tutorial.html?USERID=0&
ASSIGNID=0
-
Right Triangle Relationships:
http://illuminations.nctm.org/LessonDetail.aspx?id=L684
- Lesson on sines: http://brightstorm.com/math/geometry/basictrigonometry/trigonometric-ratios-sine/
- Lesson on cosines:
http://brightstorm.com/math/geometry/basictrigonometry/trigonometric-ratios-cosine/
- Lesson on Right Triangle Trigonometry:
http://www.khanacademy.org/video/basictrigonometry?playlist=Trigonometry
-
Review of Special Right Triangles (formative assessment lesson):
http://www.map.mathshell.org/materials/download.php?fileid=696
Enduring Understandings from this Unit
 Similar right triangles produce trigonometric ratios.
 Trigonometric ratios are dependent only on angle measure.
 Trigonometric ratios can be used to solve application
problems involving right triangles.
 properties of triangles, quadrilaterals, and other polygons
 ratios and properties of similar figures
 properties of triangles
melissa.stewart@hallco.org
November 2012
Examples & Explanations
1.
What did you notice between these three similar triangles?
melissa.stewart@hallco.org
November 2012
2.
How do these relate to the ratios in problem 1. Make sure your calculator is
in degrees.
melissa.stewart@hallco.org
November 2012
3.
A 25-foot flag pole is erected on the top of a building 10 feet from the side.
The guide wire must be anchored to the adjacent building 15 feet away and
two feet from the top of the pole. The wire is at a 50° angle with the horizon.
How long does the wire need to be?
4.
melissa.stewart@hallco.org
November 2012
 The student edition for Unit 8 can be
found at
https://www.georgiastandards.org/C
ommon-Core/Pages/Math-9-12.aspx
On the left side, please look under
mathematics. Then, the right side has
a pull-down menu to access the units.
 Additional parent guides will be
posted to the parent resource page on
http://www.hallco.org/boe/index.ph
p (right had menu) as they become
available.
melissa.stewart@hallco.org
November 2012