Suppose the radius of a circle is \color{R_COLOR}{R}
. What is its area?
We know K = \pi r^2
, so K = \pi \cdot \color{R_COLOR}{R}^2 = \color{K_COLOR}{R * R\pi}
.
Suppose the area of a circle is \color{K_COLOR}{\pi}
. What is its radius?
Suppose the area of a circle is \color{K_COLOR}{R * R\pi}
. What is its radius?
We know K = \pi r^2
, so r = \sqrt{K / \pi} = \sqrt{\color{K_COLOR}{R * R\pi} / \pi} = \color{R_COLOR}{R}
.
Suppose the diameter of a circle is \color{D_COLOR}{2 * R}
. What is its area?
First, find the radius: r = d/2 = \color{D_COLOR}{2 * R}/2 = \color{R_COLOR}{R}
.
Now find the area: K = \pi r^2
, so K = \pi \cdot \color{R_COLOR}{R}^2 = \color{K_COLOR}{R * R\pi}
.
Suppose the area of a circle is \color{K_COLOR}{\pi}
. What is its diameter?
Suppose the area of a circle is \color{K_COLOR}{R * R\pi}
. What is its diameter?
First, find the radius: K = \pi r^2
, so r = \sqrt{K / \pi} = \sqrt{\color{K_COLOR}{R * R\pi} / \pi} = \color{R_COLOR}{R}
.
Now find the diameter: d = 2r = 2\cdot \color{R_COLOR}{R} = \color{D_COLOR}{2*R}
.
Suppose the circumference of a circle is \color{C_COLOR}{2 * R\pi}
. What is its area?
First, find the radius: r = c/2\pi = \color{C_COLOR}{2 * R\pi}/2\pi = \color{R_COLOR}{R}
.
Now find the area: K = \pi r^2
, so K = \pi \cdot \color{R_COLOR}{R}^2 = \color{K_COLOR}{R * R\pi}
.
Suppose the area of a circle is \color{K_COLOR}{\pi}
. What is its circumference?
Suppose the area of a circle is \color{K_COLOR}{R * R\pi}
. What is its circumference?
First, find the radius: K = \pi r^2
, so r = \sqrt{K / \pi} = \sqrt{\color{K_COLOR}{R * R\pi} / \pi} = \color{R_COLOR}{R}
.
Now find the circumference: c = 2\pi r = 2\pi \cdot \color{R_COLOR}{R} = \color{C_COLOR}{2*R\pi}
.