Scenario: Garden Design - Design circular gardens and calculate materials needed!
You're designing a circular flower bed with a radius of 6 meters. You need to calculate the area for planting and the circumference for the border.
Questions:
1. How much area do you have for planting? (Area)
2. How much border material do you need? (Circumference)
Visual representation of the circular flower bed
Step 1: Calculate the area (planting space)
Area = π × r²
Area = π × 6²
Area = π × 36
Area = 3.14 × 36 = 113.04 m²
Step 2: Calculate the circumference (border material)
Circumference = 2 × π × r
Circumference = 2 × π × 6
Circumference = 12 × π
Circumference = 12 × 3.14 = 37.68 m
Answer: You have 113.04 m² for planting and need 37.68 m of border material.
A = π × r²
Area = π × radius²
Units: square units (m², ft², etc.)
Remember: π ≈ 3.14 (or use π button on calculator)
C = 2πr or C = πd
Circumference = 2 × π × radius
or Circumference = π × diameter
Units: linear units (m, ft, etc.)
Remember: diameter = 2 × radius
π (pi) is a special number that represents the ratio of a circle's circumference to its diameter. No matter how big or small the circle, this ratio is always the same!
π = circumference ÷ diameter ≈ 3.14159...
π is approximately 3.14 (or 22/7 for easier calculations)
Common approximation
Fraction approximation
Exact value (use calculator)
A circular swimming pool has a diameter of 10 meters. Calculate the area and circumference of the pool.
Your solution:
A circular pizza has a radius of 8 inches. Find the area of the pizza and the length of crust around the edge.
Your solution: