Area of a circle, step by step
Area of a circle squares the radius, which means getting the radius wrong costs four times over.
The question
cm²
Area of a circle marked 8 cm
- The 8 cm marked here runs from the center to the edge — that is the radius, which is what both formulas want.
- Area is π × r × r. Square the RADIUS first — only the r is squared, not the π with it: 8 × 8 = 64.
- Then multiply by π: 64 × 3.14 = 200.96 square cm.
How it works.
- 01
The 8 cm marked here runs from the center to the edge — that is the radius, which is what both formulas want.
- 02
Area is π × r × r. Square the RADIUS first — only the r is squared, not the π with it: 8 × 8 = 64.
- 03
Then multiply by π: 64 × 3.14 = 200.96 square cm.