Polygons: Angles vs. Sides

Math Lesson Plan

Students will realize the relationship between the number of sides of a polygon and the sum of its angles.

pattern blocks, overhead projector


  1. Using the overhead projector, make a polygon with pattern blocks—start with a 4-sided one.
  2. Trace the outside of the shape, then remove the blocks.
  3. Have students make their own outline of a 4-sided polygon using the same method. They can make theirs whatever shape they would like, as long as it has 4 sides.
  4. Using the tan pattern block pieces, measure the angles of the polygon you made. Do this by placing the pointy end of the tan pattern blocks in the corner (angle); continue inserting tan pattern blocks into this corner until it is covered. Do this for each corner and then add up the total number of blocks used. They should add up to 12.
  5. Have your students do the same with their polygons. They will also end up with 12.
  6. Then have your students work independently to make 5-sided polygons with the pattern blocks. They will do the same thing that they did with the 4-sided figures.
  7. Have them do this independently, adding one more side to their shape each time until you feel they have mastered it.
  8. Have students record their information in chart format: Angles vs. Sides. When students are finished, make a chart on the overhead to show what the students discovered.

Have students look at the chart and notice if there is a pattern. Ask your class why and how the knowledge of this polygon pattern is useful in the “real” world.

Notice which students did not get the correct angle counts for the polygons and those students that found a pattern before you brought up the idea. Which students were able to give some real-life uses for this knowledge?

More Lesson Plans

What is the Bill of Rights?
Day to Day Learning Guide
O’Keeffe’s Flowers
Makeshift Tambourines
Crows and Cranes
Can You Sell Your Cereal?
House of H
The African American Inventor
Picture This
The Missing Word
Where Do You Live?
Homemade Ice Cream
MLK Internet Photo Timeline
Animal Alphabetizing
Map Your House
Macaroni Pattern Necklaces
Our National Symbol
Pueblo Pottery
Perspectives in Writing
Digit Place Game
Where We Live
Coming to America
Predicting Story Outcome - June 29, 1999
Melting Ice
National Anthems of the World
LogoWriter: Create a Square
The Gettysburg Address
Cinderella Cinderella
One-difference Classification Train
Draw a Scientist
Fact versus Opinion
Shoes: Practical vs. Fashionable
Ones and Tens
Cuisenaire Fractions
Steal the Bacon
Polygons: Angles vs. Sides
Class Rap
Have We Always Had Jeans?
The Olympic Rings
Class Ketchup
Assembly Line
Bridge Building
Calculator Buying
Dancin’ Raisins
Painting Music