randRange(1, 8)

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

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

We know d = 2r, so d = 2 \cdot \color{R_COLOR}{R} = \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 );

We know d = 2r, so r = d / 2 and r = \color{D_COLOR}{2 * R} / 2 = \color{R_COLOR}{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 );

We know c = 2\pi r, so c = 2 \pi \cdot \color{R_COLOR}{R} = \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 );

We know c = 2\pi r, so r = c / 2\pi = \color{C_COLOR}{2 * R\pi} / 2 \pi = \color{R_COLOR}{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 );

We know c = \pi d, so c = \pi \cdot \color{D_COLOR}{2 * R} = \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 );

We know c = \pi d, so d = c / \pi = \color{C_COLOR}{2 * R\pi} / \pi = \color{D_COLOR}{2 * R}.

drawDiameter( R );