randRange(1, 8)

Suppose the radius of a circle is `\color{R_COLOR}{R}`. What is its diameter?

2 * R
initCircle( R ); drawRadius( R );

`d = 2\color{R_COLOR}{r}`

`\phantom{d} = 2 \cdot \color{R_COLOR}{R}`

`\phantom{d} = \color{D_COLOR}{2 * R}`

drawDiameter( R );
randRange(1, 8)

Suppose the diameter of a circle is `\color{D_COLOR}{2 * R}`. What is its radius?

R
initCircle( R ); drawDiameter( R );

`\color{D_COLOR}{d} = 2r`

`r = \dfrac{\color{D_COLOR}{d}}{2}`

`\phantom{r} = \dfrac{\color{D_COLOR}{2 * R}}{2}`

`\phantom{r} = \color{R_COLOR}{R}`

drawRadius( R );
randRange(1, 8)

Suppose the radius of a circle is `\color{R_COLOR}{R}`. What is its circumference?

Math.PI * 2 * R
initCircle( R ); drawRadius( R );

`c = 2\pi \color{R_COLOR}{r}`

`\phantom{c} = 2 \pi \cdot \color{R_COLOR}{R}`

`\phantom{c} = \color{C_COLOR}{2 * R\pi}`

drawCircumference( R );
randRange(1, 8)

Suppose the circumference of a circle is `\color{C_COLOR}{2 * R\pi}`. What is its radius?

R
initCircle( R ); drawCircumference( R );

`\color{C_COLOR}{c} = 2\pi r`

`r = \dfrac{\color{C_COLOR}{c}}{2\pi}`

`\phantom{r} = \dfrac{\color{C_COLOR}{2 * R\pi}}{2\pi}`

`\phantom{r} = \color{R_COLOR}{R}`

drawRadius( R );
randRange(2, 16) / 2

Suppose the diameter of a circle is `\color{D_COLOR}{2 * R}`. What is its circumference?

Math.PI * 2 * R
initCircle( R ); drawDiameter( R );

`c = \pi \color{D_COLOR}{d}`

`\phantom{c} = \pi \color{D_COLOR}{2 * R}`

`\phantom{c} = \color{C_COLOR}{2 * R\pi}`

drawCircumference( R );
randRange(2, 16) / 2

Suppose the circumference of a circle is `\color{C_COLOR}{2 * R\pi}`. What is its diameter?

2 * R
initCircle( R ); drawCircumference( R );

`\color{C_COLOR}{c} = \pi d`

`d = \dfrac{\color{C_COLOR}{c}}{\pi}`

`\phantom{d} = \dfrac{\color{C_COLOR}{2 * R\pi}}{\pi}`

`\phantom{d} = \color{D_COLOR}{2 * R}`

drawDiameter( R );