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Lesson Plan
Illustrative Mathematics

Finding an Unknown Angle

For Teachers 4th - 6th Standards
Teach your class how to apply their knowledge of geometry as they explore the unknown. In order to find an unknown angle, students must understand that rectangles have four interior right angles, that right angles have 90 degrees, and...
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Lesson Plan
EngageNY

Unknown Angles

For Students 9th - 10th Standards
How do you solve an equation like trigonometry? Learners apply their understanding of trigonometric ratios to find unknown angles in right triangles. They learn the meaning of arcsine, arccosine, and arctangent. Problems include basic...
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Lesson Plan
EngageNY

Solve for Unknown Angles—Angles in a Triangle

For Teachers 9th - 10th Standards
Assist your class with each angle of geometry as they use exterior angles to form linear pairs with adjacent interior angles. They cover multiple vocabulary terms and work practice problems, complete with justifications, before taking an...
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Worksheet
Curated OER

Measurements of Unknown Angles

For Students 6th - 8th
In this geometry skills practice worksheet, students respond to 9 questions that require them to calculate the measurements of the unknown angles.
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Worksheet
Math Mammoth

Calculating Angles in a Triangle 2

For Students 5th - 6th
In this geometry worksheet, students calculate unknown angles in diagrams of 3 triangles. They draw and answer short answer questions about angles. They then calculate the designated angles in 2 more diagrams.
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Interactive
Curated OER

Five Find the Unknown Angle Interactive Problems

For Students 10th - Higher Ed
In this unknown angle worksheet, students use trigonometry functions in five problems to find the unknown angles.  Students may check their solutions and receive hints by using the "Check" and "Hint" button found at the bottom of the page.
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Worksheet
Curated OER

Angles, Bearings and Maps

For Students 7th - 8th
In this angles, bearings and maps worksheet, students measure angles and classify, calculate the size of unknown angles, and complete related multiple choice and word problems.
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Worksheet
Curated OER

Finding Unknown Angles

For Students 10th
In this finding unknown angles learning exercise, 10th graders find each numbered angle's measure for 20 different angles shown in the diagrams. They calculate the size of an angle when the other two angles are known to equal 180...
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Lesson Plan
EngageNY

One-Step Problems in the Real World

For Teachers 6th Standards
Mirror, mirror on the wall, which is the fairest resource of them all? Individuals write and solve one-step equations for problems about angle measurement, including those involving mirrors. Both mathematical and real-world problems are...
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Instructional Video10:36
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Flipped Math

Inverse Trig Ratios

For Students 9th - 12th Standards
Put trigonometric ratios into inverse. Scholars learn how to find an unknown angle in a right triangle by using inverse trigonometric ratios. The pupils understand how the inverses undo a trigonometric ratio to provide the angle measure....
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Worksheet
Curated OER

Parallel Lines and Types of Angles

For Students 5th - 6th
In this angles and parallel lines activity, students solve 40 problems that pertain to parallel lines, supplementary, vertical, corresponding and alternate angles. There is instruction on the page with examples. This page is intended as...
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Worksheet
Curated OER

Angles on a Line and on a Point

For Students 6th - 7th
In this angles worksheet, students solve 24 problems pertaining to angle measurements on a line and on a point. There are also calculations of adjacent angles and supplementary angles. The page is intended as an online activity but can...
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Lesson Plan
EngageNY

An Area Formula for Triangles

For Teachers 11th - 12th Standards
Use a triangle area formula that works when the height is unknown. The eighth installment in a 16-part series on trigonometry revisits the trigonometric triangle area formula that previously was shown to work with the acute triangles....
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Worksheet
Helping with Math

Supplementary Angles

For Students 4th - 6th Standards
Pupils calculate the measurement of supplementary angles when one angle is known. The one-page assignment has six simple problems. It contains links to related resources as well as the answer key. Be aware that although the publisher...
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Lesson Plan
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NASA

The Lunar Lander – Ascending from the Moon

For Teachers 10th - 12th Standards
What angle? Groups determine the height of the lunar lander as it ascends from the surface of the moon and calculate the angle of elevation of the lunar lander at specific times and distances. The provided series of questions lead the...
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Worksheet
Curated OER

Polygons

For Students 6th - 10th
In this polygons worksheet, students read about and complete many activities involving triangles, angles, and symmetry. Students complete 17 pages of activities.
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Worksheet
Curated OER

Trigonometric Function

For Students 10th
In this trigonometric function instructional activity, 10th graders solve and complete 26 various types of problems. First, they use a calculator to find each value and each angle. Then, students state which trig function they used to...
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Lesson Plan
Curated OER

Geometry of Triangles Using a Protractor

For Teachers 7th
Seventh graders use a protractor to measure angles and solve a problem involving distance. In this measuring angles with a protractor lesson plan, 7th graders calculate the distance of a line on a diagram by using a protractor to measure...
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Worksheet
Curated OER

Right Triangle Trigonometry

For Students 12th
In this trig activity, 12th graders identify the angles of a tight triangle using sine, cos and tan combined with the given sides. There are 23 problems broken down in 4 sections.
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Assessment
Bowland

German or English?

For Teachers 6th - 8th
Sprechen sie Deutsch? Future cryptographers must decide whether an unknown text is written in English or in German. They use provided pie charts about the frequency of words in the English and German languages to help make their decisions.
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Activity
Big Kid Science

Measuring Shadows Using an Ancient Method

For Teachers 8th - 12th Standards
How did ancient peoples determine the height of really tall objects? Young scientists and mathematicians explore the concept of using shadows to measure height in a hands-on experiment. Paired pupils measure shadows, then calculate the...
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Lesson Plan
Curated OER

The Trig To Soccer

For Teachers 9th - 12th
Students are given the background information to open the lesson: Suppose a penalty kicker in soccer could choose where he could kick from, as long as he stayed on the back line of the penalty area. Would he have a better chance of...
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Worksheet
Curated OER

Angles, Symmetry, and Quadrilaterals in Four Exercise Sets

For Students 8th - 11th
In this angles learning exercise, students calculate the size of angles, draw lines of symmetry, and form quadrilaterals in four exercise sets.  The solutions are provided.
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Activity
Curated OER

Task: Miniature Golf

For Teachers 6th - 10th Standards
"Fore!" All right, no one really yells this out in miniature golf, but this well-defined activity will have your charges using lots of numbers in their unique design of a miniature golf hole. Included in the activity criteria is the...