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Foldable: Law of Sines and Cosines By Caryn Owings

Table of Contents Copy Right Information: ..................................................................................................................................................... 2

Teaching Idea. ......................................................................................................................................................................... 3

Inside-Student Version ............................................................................................................................................................ 4

Outside – Student Version ...................................................................................................................................................... 5

Inside-Completed Version ....................................................................................................................................................... 6

Outside - Completed ............................................................................................................................................................... 7

Copy Right Information:

This package is copyrighted 2013 (updated 2017) by Caryn Owings: Caryn Loves Math

All rights reserved. Purchase of this unit entitles the purchaser the right to reproduce the pages in limited

quantities for classroom use only. You may also duplicate for use in with your students in your special

education and English Language Learners support rooms. Duplication for an entire school, an entire school

system or commercial purposes is strictly forbidden without written permission from the publisher.

Please contact me if you wish to be granted special permission. I can be contacted using the questions

section of my TPT store.

www.teacherspayteachers.com/Store/Caryn-Loves-Math

Copying any part of this product and placing it on the Internet in any form (even a personal/classroom

website) is strictly forbidden and is a violation of the Digital Millennium Copyright Act (DMCA). These items

can be picked up in a google search and then shared worldwide for free.

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Teaching Idea.

This foldable is designed to help students decide when to use the law of sine and the law of cosine.

2 versions are included: One is for students to complete and one that is already completed. The completed version is

great for para to use when helping students. If you have ELL or SPED students, you can send the completed version

to their resource teacher to give added help. I also use the completed version with absent students, I can either give

them one already completed or let them copy the completed version.

Once the foldable is completed, I encourage my students can use it to complete homework problems.

How to use the foldable

Students decide what information about sides & angles they have been given. Then the foldable shows them which

law to use…

When they open the foldable it shows the formula and an example of how to work a sample problem.

How to put together

Print the foldable front to back.

When looking at the inside…cut around the outside of the foldable

Glue into your student notebook.

Fold along dotted line

Cut the dotted line

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Inside-Student Version

Example:

1) Start by labeling the triangle

2) Pick the correct formula

3) Substitute In what we know 4) Solve

Example:

1) Start by labeling the triangle

2) Pick the correct formula

3) Substitute In what we know

4) Solve

Law of Sines Law of Cosines

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Outside – Student Version

If you have …

Angle-Side-Angle or Angle-Angle-Side

If you have …

Side-Side-Side or Side-Angle-Side

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Inside-Completed Version

Example: Find the length of 𝐶𝐵̅̅ ̅̅

1) Start by labeling the triangle / C = 180 -74 -51 = 55o

2) Pick the correct formula

sin 𝐴

𝑎=

sin 𝑪

𝒄

3) Substitute In what we know

sin 74

𝑎=

sin 55

10

4) Solve 𝒂 sin 55 = 10 sin 55

𝒂 = 10 sin 74

sin 55

𝒂 ≈ 11.7 𝑖𝑛

Example:

1) Start by labeling the triangle

2) Pick the correct formula

𝒂2 = 𝒃2 + 𝒄2 − 2𝒃𝒄 cos 𝑨

3) Substitute In what we know

𝒂2 = 𝟗2 + 𝟏𝟓2 − 2(𝟗)(𝟏𝟓) cos 𝟑𝟎 4) Solve

𝒂2 ≈ 72.173

𝒂 ≈ 8.5 𝑐𝑚

sin 𝑨

𝒂=

sin 𝑩

𝒃=

sin 𝑪

𝒄

𝒂2 = 𝒃2 + 𝒄2 − 2𝒃𝒄 cos 𝑨

𝒃2 = 𝒂2 + 𝒄2 − 2𝒂𝒄 cos 𝑩

𝒄2 = 𝒂2 + 𝒃2 − 2𝒂𝒃 cos 𝑪

Law of Sines Law of Cosines

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Outside - Completed

If you have …

Angle-Side-Angle or Angle-Angle-Side

If you have …

Side-Side-Side or Side-Angle-Side

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Thanks for your purchase

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All the graphics in this product were designed by me