Exploring Pi (Grade 4 Math)

Exploring Pi (Grade 4 Math)

Read each question carefully and follow the instructions. Use a ruler and string for measuring if needed.

A circle is a round shape. Every point on the edge of a circle is the same distance from its center.

Look at the parts of a circle:

The **radius** is the distance from the center to any point on the edge of the circle.

The **diameter** is the distance across the circle, passing through the center. It's twice the radius.

The **circumference** is the distance around the circle (its perimeter).

1. The distance from the center of a circle to its edge is called the  .

2. The distance across a circle, through its center, is called the  .

3. The distance around the circle is called the  .

4. Draw a circle with a diameter of 6 cm. What is its radius?

5. Find three circular objects in your classroom (e.g., a clock, a plate, a cup). For each object, use a string and ruler to measure its circumference and then its diameter. Record your measurements in the table below.

6. For each object you measured, divide its Circumference by its Diameter. What do you notice about the numbers you get? Write down your observations.

You should have noticed that the answer is always close to 3.14. This special number is called **Pi** (pronounced "pie"), and its symbol is **π**.

Pi is the ratio of a circle's circumference to its diameter. It's always the same for ANY circle!

7. What does Pi (π) represent?

8. Approximately what number is Pi equal to?

9. Pi is a different number for small circles than for large circles.