Interactive
Curated OER

Angles in a Triangle

For Students 10th
For this geometry worksheet, 10th graders determine the measure or measures of the missing angle(s) in a triangle. The one page interactive worksheet contains four questions. Answers and hints are included. 
Interactive
Shodor Education Foundation

Squaring the Triangle

For Students 8th - 12th Standards
Teach budding mathematicians how to square a triangle with an interactive that shows a graphical proof of the Pythagorean Theorem. Pupils alter the lengths of the legs using sliders. Using the inputted lengths, the applet displays the...
Interactive
Curated OER

Try These Angles! Exploring Angles: Post Test

For Students 5th - 8th
In this angles worksheet, students answer multiple choice questions about angles on their own and angles inside shapes. Students complete 10 multiple choice questions.
Interactive
Curated OER

Try These Angles! Exploring Angles

For Students 5th - 8th
In this angles activity, students answer multiple choice questions about different types of angles in shapes. Students complete 10 questions.
Interactive
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GeoGebra

Conjectures and Proof

For Students 9th - 12th Standards
Transform proofs using triangle rotations. By rotating a triangle around various points, class members develop proofs. Participants prove relationships of alternative interior angles formed by parallel lines and the sum of the interior...
Interactive
Curated OER

Polygons Multiple Choice

For Students 9th - 10th
In this geometry worksheet, students identify the interior and exterior angles using the angle sum theorem. They identify and solve quadrilaterals using properties of quadrilaterals. There are 12 questions with an answer key.
Interactive
Curated OER

All About Quadrilaterals

For Students 7th
In this quadrilateral post test worksheet, 7th graders answer ten multiple choice questions by solving questions based on quadrilaterals and angles of quadrilaterals. This is an interactive worksheet.
Interactive
Curated OER

English Vocabulary Skills: AWL Sublist 4 - Exercise 4b

For Students 9th - 12th
For this online interactive English vocabulary skills worksheet, students answer 10 matching questions which require them to fill in the blanks in 10 sentences. Students may submit their answers to be scored.
Interactive
Curated OER

SAT Practice Test

For Students 9th - 12th
In this secondary mathematics worksheet, high schoolers assess their readiness for the SAT test.  The one page, interactive worksheet contains ten problems.  Solutions are not provided. 
Interactive
Mangahigh

Mangahigh: Shape: Proof of the Sum of the Angles in a Triangle

For Students 9th - 10th Standards
Determine that all angles in a triangle equal 180 degrees.
Interactive
Walter Fendt

Walter Fendt: Sum of Angles in a Triangle

For Students 9th - 10th
A short interactive activity to show that the sum of the angles of a triangle is 180 degrees.
Interactive
Calculator Soup

Calculator Soup: Triangle Theorems Calculator

For Students 9th - 10th Standards
Each calculation option has sub-bullets that list the sequence of methods used in this calculator to solve for unknown angle and side values including Sum of Angles in a Triangle, Law of Sines, and Law of Cosines.
Interactive
National Council of Teachers of Mathematics

Nctm: Illuminations: Angle Sums

For Students 9th - 10th
Students may use this computer applet to explore angle sums of triangle, quadrilaterals, pentagons and hexagons.