Given a pair of parallel lines and a triangle in between, geometers prove that the sum of the interior angles is 180 degrees. This quick quest can be used as a pop quiz or exit ticket for your geometry class.

How can learners use algebra to solve a geometry problem? Help learners create an equation that shows the relationship between the number of sides of a polygon and the sum of the interior angles. Students are asked to divide the...

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...

After learning that the sum of interior angles for triangles is 108 degrees, take it further to show that the sum of angles in any polygon is the same! Using hexagons, pupils practice finding the measure of the six congruent angles. Make...

This can be used as a critical thinking exercise in congruence or as a teaching tool when first introducing the concept. Four octagons are arranged in such a way that a square is formed in the middle. With this information, geometry...

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,...

Math can be a work of art! Reach your artistic pupils as they explore angle measures. A creative set of five problems of varying levels has young learners study interior and exterior angle measures of polygons. The introductory levels...

Bringing together the young artists and the young organizers in your class, this lesson plan takes that popular topic of tessellations and gives it algebraic roots. After covering a few basic properties and definitions, learners attack...

Your geometry learners explore Angle-Side-Angle congruence in this collaborative task. The sum of the interior angles of all triangles being one hundred eighty degrees, is the key learners will discover as they explain their reasoning...

This task asks learners to prove that the segment joining the midpoints of two sides of a parallelogram is both congruent and parallel to an adjacent side of the parallelogram. The activity would be good to use in a discussion about how...

Draw a triangle with exterior angle. Measure the exterior angle and each remote interior angle. Use the Alpha hand to check that the sum of the remote interior angles is always equal to the exterior angle.

This multimedia Learn Alberta math resource looks at angles of a triangle in the context of building bikes and choosing bike sizes. The accompanying interactive component lets students explore build different sized triangles while...

In this activity, students will measure angles and investigate the relationships between interior and exterior angles of a triangle. They understand the definition of interior angles, exterior angles, adjacent angles, supplementary...

This activity is designed as an introduction to using the Carbri Jr. application on the TI-83+/84+ calculators. Students are guided through the menu system and are shown how to draw triangles, quadrilaterals and and a pentagon. Perimeter...

Students construct a line parallel to the base of a triangle and measure the angles formed. They use the construction to prove that the sum of the measures of the interior angles of a triangle is 180 degrees.

In this activity, students investigate the sum of the measures of the interior angles of a triangle. They will explore interior angles, and their relationship with the exterior angles of a triangle.

This activity will allow students to use Cabri Jr. to find the sum of the measures of interior angles of convex polygons and visually see how the Interior Angle Sum Theorem works.

Try these three problems about finding the measures of different angles that arise from diagrams involving parallel lines and transversals. Detailed solutions are written out for these three problems of moderate difficulty.

In this activity, use an interactive, and investigative approach to determining the sum of the interior angles of a quadrilateral. They use Cabri Jr. to draw, measure, and calculate the characteristics of the angles of quadrilaterals.

In this activity, students learn about the sum of the angles in a triangle. They understand triangles and their interior angles.

Students will expore the interior and exterior angle of 3 polygons and develop the formula to calculate the sum of degrees without the measurement of the angles being taken.

Students investigate the sum of the measures of the interior angles of a triangle. This activity explores interior angles, and their relationship with the exterior angles of a triangle [Requires Adobe Reader.]