Question

the radius of a circle is 8 units.
drag and drop the tiles to complete the equation for the circumference and then calculate the circumference.
c = × ×
c =
tiles: 4, 8π, 16, 16π, 2, π, 8

Explanation:

Step1: Recall Circumference Formula

The formula for the circumference \( C \) of a circle is \( C = 2\pi r \) (where \( r \) is the radius) or \( C=\pi d \) (where \( d \) is the diameter, and \( d = 2r \)). Given \( r = 8 \), first find \( d \): \( d=2\times8 = 16 \).

Step2: Substitute into Formula

Using \( C = \pi d \), substitute \( d = 16 \). So \( C=\pi\times16=16\pi \). Or using \( C = 2\pi r \), substitute \( r = 8 \): \( C = 2\times\pi\times8=16\pi \).

Answer:

The equation for circumference is \( C = 2\times\pi\times8 \) (or \( C=\pi\times16 \)) and the circumference is \( 16\pi \) units.