Worksheet
Curated OER

Missing Angle Measures

For Students 5th - 8th
In this missing angle measures worksheet, students subtract the angle that is given from 180' to find the missing angle measure. Students complete 6 problems.
Handout
McGraw Hill

Triangles

For Students 4th - 7th Standards
After reviewing characteristics of seven types of triangles, young geometers discover how to find the missing angle of a triangle. Then, they practice identifying triangles, find missing angles, and find missing side lengths of...
Lesson Plan
Willow Tree

Angle Sum Property of Triangles

For Students 8th - 11th Standards
All triangles have some things in common. Using these properties of triangles, learners find missing angle measures. Scholars use the Angle Sum Property and properties of special triangles throughout the lesson.
Activity
Illustrative Mathematics

Find the Missing Angle

For Teachers 7th - 9th Standards
This one activity requires young geometers to pull together information they are currently learning with things they have learned previously. Here they rely on understanding something about parallel lines, alternative interior angles,...
Worksheet
Curated OER

Find Missing Angles of Triangles

For Students 5th - 6th
In this triangles worksheet, students find the missing angles of a set of 4 triangles. Answers are included on page 2.
Handout
Charleston School District

The Sum of Angles in a Triangle

For Students 8th Standards
An informative lesson contains a brief explanation of how the sum of the angles of a triangle is a line. The lesson continues with determining the missing angle in a triangle, or solving for a variable. Using the sum of the...
Lesson Plan
Hotchalk

Triangle Sum Theorem

For Teachers 8th - 10th Standards
Your visual geometry learners will appreciate triangle drawings as they model the triangle sum theorem and algebraically solve to find the missing interior angle in a triangle. Practice problems increase in complexity and vary in their...
Worksheet
Curated OER

Angle Sum of Triangles and Quadrilaterals

For Students 9th - 12th
In this angle sum worksheet, students find missing angles of 20 triangles and quadrilaterals.  Students find the missing angle in each polygon by using the total degrees of each and given angle measures.
Assessment10:41
Mathed Up!

Angles: Parallel Lines

For Students 9th - 11th Standards
Viewers are presented with seven problems with parallel lines and angle relationships and must use the given information to find the measures of specific angles. To finish, they explain their process in finding the measures in the...
Worksheet
Curated OER

Triangles

For Students 6th - 10th
In this triangles worksheet, learners solve for the missing angles and missing sides on the triangles given. Students complete 12 problems total.
Worksheet
Curated OER

Right Triangle Trigonometry: Finding Missing Sides and Angles

For Students 9th - 11th
In this right triangle trigonometry worksheet, students find the measure of specified angles. Students determine the length of the missing side of a right triangle. This four-page worksheet contains 24 problems. Answers to the worksheet...
Worksheet
Curated OER

Triangle Fundamentals

For Students 8th - 12th
For this geometry worksheet, students observe a triangle marked with three angles and are given two measures to find the missing third measure. A second diagram is given with six angles. There are 20 questions.
Lesson Plan
Willow Tree

Ratios and Proportions with Congruent and Similar Polygons

For Students 8th - 11th Standards
Investigate how similar and congruent figures compare. Learners understand congruent figures have congruent sides and angles, but similar figures only have congruent angles — their sides are proportional. After learning the...
Assessment
Mathed Up!

Sine and Cosine Rules and Area of Triangles

For Students 9th - 12th
Learners discover how to find missing sides and angles using trigonometry. Scholars first watch a video covering the Law of Sines and Cosines, as well as the area formula for a triangle. To test their knowledge, they complete a worksheet...
Worksheet
Curated OER

Geometry Worksheet- Angle

For Students 9th - 11th
In this geometry worksheet, students solve questions dealing with angles, triangles, and quadrilaterals. They calculate the missing angle. There are 2 questions.
Lesson Plan
EngageNY

More About Similar Triangles

For Teachers 8th Standards
Determine whether two triangles are similar. The lesson presents opportunities for pupils to find the criterion needed to show that two triangles are similar. Scholars use the definition of similarity to find any missing side...
Worksheet
Curated OER

Right Triangle Trigonometry

For Students 10th
In this geometry worksheet, 10th graders use right triangle trigonometry to find the missing angle measure.  The two page worksheet contains fourteen problems.  Answers are provided. 
Worksheet
Curated OER

Finding Angles in Right Triangles

For Students 10th
In this geometry worksheet, 10th graders use right triangle trigonometry to solve application problems in which they find the measure of the missing angle in a right triangle.  The two page worksheet contains five free response...
Assessment6:43
Mathed Up!

Angles in Triangles and Quadrilaterals

For Students 8th - 10th Standards
This short video show viewers how to connect the sum of the angles in a triangle to other angle measurements. Pupils determine the missing measures for angles involved with triangles and quadrilaterals. Class members then must explain...
Worksheet
Curated OER

Determine the Measure of an Angle of a Right Triangle.

For Students 10th - 11th
In this geometry worksheet, students solve word problems by finding the values of missing angles and missing sides of triangles. They review their trigonometric properties of a right triangle. There are 9 problems with an answer key.
Worksheet
Curated OER

Angles in Polygons

For Students 10th - 12th
For this angles in polygons worksheet, learners determine the value of a missing angle measure. They find the value of interior angles and exterior angles. Polygons include triangles, quadrilaterals, pentagons, and hexagons. This...
Worksheet
Curated OER

Isosceles Triangles

For Students 9th - 12th
In this geometry worksheet, high schoolers set up equations to solve for the missing angle or side of an isosceles triangle. All the equations turn out to be linear and not quadratic. There are 15 questions. 
Interactive
Curated OER

Mixed Right Triangles

For Students 10th
In this geometry learning exercise, 10th graders use right triangle trigonometry to find the missing angle measure or side length in right triangles. The one page interactive learning exercise contains ten questions. Answers and hints...
Worksheet
Curated OER

Trigonometric Triangles

For Students 9th - 11th
In this trigonometry worksheet, students find the missing angle and sides given the 6 trigonometric values. There are 6 questions with an answer key.