Illustrative Mathematics
Sum of Angles in a Polygon
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...
Curated OER
Tile Patterns II: Hexagons
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...
Willow Tree
Interior Angles, Exterior Angles, and Diagonals of Polygons
How does the number of sides of a polygon affect the angle measures? Learners recognize a pattern in finding the total measure of interior and exterior angles and the number of diagonals. They use the patterns to calculate...
Virginia Department of Education
Angles in Polygons
Polygons — it's all about the angles. Groups work with dynamic geometry software to find the sum of the measures of the angles of various polygons. After finding the information for several polygons, the groups generate a formula that...
Curated OER
Finding the Sum of the Exterior and Interior Angles of a Polygon
Students find the sum of the angles of a polygon and construct a polygon given the number of sides. In this polygon lesson plan, students draw large polygons on the floor of the room. They measure the length of each side and the interior...
Curated OER
Sum of Exterior Angles of Polygons
Have fun calculating angles for different polygons. The class differentiate the relationship between the interior and exterior angles of polygons. They discuss linear pair as it related the polygons and their angles. This is done as they...
Curated OER
Investigation - Adrienne's Pattern Block Angles
Fifth graders investigate possible solutions to a word problem. They explore properties of polygons and right angles. Students demonstrate proper angle measurement. Students discover patterns.
Curated OER
Interior Angles of Regular Polygons
Learners investigate the interior angles of a triangle. In this geometry instructional activity, students create the formula to calculate the angles inside a triangle. They observe the total sum of a triangles angle on the navigator.
Willow Tree
Angle Sum Property of Triangles
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.
Curated OER
Interior/Exterior Polygon Angles and Tessellations
Students discover the sum of the interior and exterior angles of several polygons. In this Geometers sketchpad instructional activity, students work in groups to find the stated measurements of triangles, quadrilaterals, pentagons and...
Curated OER
Exploring Characteristics of Triangles
Young scholars draw triangles and explore the classification of each using the measures of interior angles and lengths of sides. They investigate the sum of the interior angles of various triangles and conjecture and prove the theorem:...
Curated OER
Polygons
Students investigate the concepts related to the study of polygons. They specifically look at how angles is related. The lesson includes specific examples and dialogue to be used by the teacher during direct instruction and independent...
Curated OER
Around The Stop Sign
Students analyze a drawing of a regular octagon inscribed in a circle to determine angle measures, using knowledge of properties of regular polygons and the sums of angles in various polygons to help solve the problem. They use...
Curated OER
Polygons: Angles vs. Sides
Young scholars analyze the relationship between the number of sides of a polygon and the sum of its angles. Pattern blocks are utilized to trace the outside of the shapes. They make their own outline of a four-sided polygon from the...
Curated OER
Tile Patterns I: Octagons and Squares
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...
Improving Measurement and Geometry in Elementary Schools
The Sum of the Interior Angles of a Polygon
Junior geometers discover that polygons can be decomposed into triangles and that the number of triangles can be determined by a rule. Note that the Geometer’s Sketchpad® software is required to carry out all components of this...
Curated OER
Patterns in the Sums of Polygon Angles
Sixth graders discover the patterns of sums of polygon angles. In this math lesson plan, 6th graders study the properties of geometric shapes to solve problems as they participate in hands-on activities.
Curated OER
Lesson Exchange: Polygons (Middle, Mathematics)
Students discover the relationship between the sides of a polygon and the number of diagonals that can be drawn from one vertex, the number of triangles that those diagonals form, and the sum of the interior angles of that polygon.
Curated OER
Polygons and Diagonals
Learners practice measuring the interior angles of given regular polygons and create a formula for finding the measure of th interior angles of any polygon. They determine the relationships between the number of vertices's or sides in a...
Curated OER
Sum of Interior/Exterior Angles with Wilbur
Students identify the interior and exterior measures of polygons. In this geometry lesson, students identify the formula for interior angles of polygons. They differentiate between triangular and polygons angles.
Curated OER
Tessellation Trial and Error
In this interactive lesson, students review attributes of equilateral polygons. They are introduced to the concept of a tessellation. Using protractors and pre-cut shapes, students arrange a variety of tiles to create tessellations. They...
Curated OER
Polygon Sum Conjecture
Students calculate the sum of the angles of a polygon. In this geometry lesson plan, students use the interior angle formula of polygon based on the number of sides of the polygon. They identify the missing angle using algebra.
Curated OER
Intro To Quadrilaterals
Students engage in a lesson that is concerned with the concept of quadrilaterals and how they are used to create a rectangle for a door. They create a drawing of a quadrilateral while finding the sum of the angles. They practice problems...
Curated OER
Formula Determination
Students derive a formula for the interior degrees in any convex polygon. In this geometric figure lesson plan, students determine the shapes of various polygons and the number of triangles formed. They use this information to derive the...