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 );