What Makes a Circle Special?
Every circle has three important measurements:
The radius is the distance from the center to the edge. The diameter goes all the way across through the center. The circumference is the special name for a circle's perimeter - the distance all around it!
How They Relate to Each Other
1️⃣ The diameter is always 2 × radius: \( d = 2r \)
2️⃣ The circumference is about 3.14 × diameter: \( C = πd \)
3️⃣ π (pi) is a special number ≈ 3.14159 that helps with circles
Let's Practice Together!
Example 1: Pizza Measurements
Your pizza has a diameter of 12 inches. What is its radius and circumference?
Example 2: Bike Wheel
A bike wheel has a radius of 14 inches. How far will it travel in one full turn?
Parent Tips 🌟
- Kitchen Math: Use plates, lids, and cookies to practice measuring diameters and calculating circumferences.
- Outdoor Exploration: Measure tree trunks, hula hoops, or bicycle wheels to find real-world circles.
- Memory Trick: Teach "Radius is half, diameter's whole, circumference is pi around we go!" as a fun rhyme.