Grade 7 · Geometry
Circumference and Area of Circles
Two formulas, one number, infinite depth. Pi (π) is the ratio of every circle's circumference to its diameter — a relationship students can discover by measuring. Once C = πd is understood, A = πr² follows from the same wedge-rearrangement argument used in Grade 6, now applied more formally.
LESSON VIDEO
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Lesson video
A short walkthrough to play in class or assign for flipped/at-home viewing.
WHAT STUDENTS WILL LEARN
✓Identify radius, diameter, and circumference and describe their relationships
✓Calculate circumference using C = π × d
✓Calculate area using A = π × r²
✓Solve problems involving circles in real-world contexts