Lessons for G.GMD.A.1
Area of a circleCut into wedges, lay them into a near-rectangle, read off pi r squared.Lesson
Cavalieri's principleTwo solids whose cross sections match in area at every height have the same volume, even if one leans.Lesson
CircumferencePi as the ratio of around to across, and the formula that follows.Lesson
Why the volume formulas hold: dissection, slicing and CavalieriInformal arguments for the cylinder, pyramid, cone and sphere volume formulas, by dissection, by slicing and by Cavalieri's principle.Lesson
Volume of solidsOne third of the matching prism or cylinder, and the sphere formula.Lesson
Why the circle area formula worksThin wedges cut from a circle and interlocked make a near rectangle of radius by half the circumferenceLesson
Printable Worksheets
Area of a circle worksheet (PDF)Printable worksheet with answer keyPreview
Cavalieri's principle worksheet (PDF)Printable worksheet with answer keyPreview
Circumference worksheet (PDF)Printable worksheet with answer keyPreview
Why the volume formulas hold: dissection, slicing and Cavalieri worksheet (PDF)Printable worksheet with answer keyPreview
Why the circle area formula works worksheet (PDF)Printable worksheet with answer keyPreview