Question

1. find the circumference of the circle answer: ______

Explanation:

Step1: Recall the formula for the circumference of a circle

The formula for the circumference \( C \) of a circle is \( C=\pi d \) (where \( d \) is the diameter) or \( C = 2\pi r \) (where \( r \) is the radius). From the diagram, the diameter \( d = 20 \).

Step2: Substitute the diameter into the formula

Using \( C=\pi d \), substitute \( d = 20 \). So \( C=\pi\times20=20\pi \). If we use \( \pi\approx3.14 \), then \( C = 20\times3.14 = 62.8 \).

Answer:

If we use \( \pi\approx3.14 \), the circumference is \( 62.8 \); in terms of \( \pi \), it is \( 20\pi \). (Commonly, if a numerical value is expected, \( 62.8 \) or \( 20\pi \) depending on the requirement. Here, with \( \pi\approx3.14 \), \( 20\times3.14 = 62.8 \))