A circle is inscribed in a square. Write and simplify an expression for the ratio of the area of the square to the area of the circle. For a circle inscribed in a square, the diameter of the circle is equal to the side length of the square.
Given:
circle inscribed in a square.
Side length of the square = diameter of the circle.
Let x side length and diameter.
Area of a square = x²
Area of a circle = πr²
r = radius ; half of the diameter. = x/2
Area of a circle = π (x/2)² or π (x²/4)
Ratio of the area of the square to the area of the circle
x² : π(x²/4) or x² / πx²/4
x² 4/πx² = 4/π
The area of a circle with a diameter d is \(\frac{ \pi d^4}{4}\) and the area of a square whose side is the diameter d of the circle is \(d^2\).
The ratio of the area of a square to the area of a circle is
\(d^2 : \frac{ \pi d^2}{4}\)
Since there is a common term on both sides, we cancel \(d^2\) and get the final ratio of:
\(1: \frac{ \pi }{4}\)