Q3, W8: Geometry (February 25-March 1)

TeacherKristin Andreason
Subject AreaGeometry Honors
Grade Level8
Week #Eight
Unit of InstructionUnit 6: Two-Dimensional Measures
Standard(s) Taught

MAFS.912.G-GMD.1.1:  Give an informal argument for the formulas for the circumference of a circle, area of a circle, volume of a cylinder, pyramid, and cone. (Use dissection arguments, Cavalieri’s principle, and informal limit arguments.)

Learning Targets and Learning Criteria
  • define regular polygons.
  • inscribe a regular polygon in a circle and break it into many congruent triangles to find its area.
  • explain and use the dissection method on regular polygons to generate an area formula for regular polygons A = ½ × apothem × perimeter (A = aP).
  • calculate the area of a regular polygon A = ½ × apothem × perimeter   (A = ½aP).
  • use pictures to explain that a regular polygon with many sides is nearly a circle, its perimeter is nearly the circumference of a circle, and that its apothem is nearly the radius of a circle.
  • substitute the “nearly” values of a many sided regular polygon into   A = ½ × apothem × perimeter (A = ½aP) to show that the formula for the area of a circle is A = LaTeX: \piπr2.
Classroom Activities


  • Finish Real-Life Area of Compound Figures (2nd period)
  • Area of regular polygons notes, graphic organizer, and foldable
  • Start area of regular polygons scavenger hunt


  • Continue working on Area of regular polygons scavenger hunt


  • Finish the area of regular polygons scavenger hunt
  • Do the Real Life challenge question
Assignments Due
  • Area of regular polygons scavenger hunt due on March 1st.
Additional Resources

All IEP and ESOL accommodations provided daily.