Question 9 of 42advanced🔍 AnalyzeLong Answer5 marks

A hexagon is inscribed in a circle of radius rr. Show that the ratio of the area of the hexagon to the area of the circle is equal to 332π0.827\frac{3\sqrt{3}}{2\pi} \approx 0.827. Can you see why the answer is exactly twice the answer to Question 8?

(i)
Answer

The ratio of the area of the hexagon to the area of the circle is 33\sqrt{3}/2π \approx 0.827.

(ii)
Answer

The answer is exactly twice the answer to Question 8 because a hexagon inscribed in a circle has exactly twice the area of an equilateral triangle inscribed in the same circle.

Explanation

For part (i), a regular hexagon inscribed in a circle of radius rr can be divided into 6 equilateral triangles, each with side rr. The area of one equilateral triangle is 34r2\frac{\sqrt{3}}{4}r^2, making the hexagon's total area 6×34r2=332r26 \times \frac{\sqrt{3}}{4}r^2 = \frac{3\sqrt{3}}{2}r^2. Dividing this by the circle's area πr2\pi r^2 yields the ratio 332π\frac{3\sqrt{3}}{2\pi}.

For part (ii), Question 8 involves an equilateral triangle inscribed in a circle of radius rr, which has an area of 334r2\frac{3\sqrt{3}}{4}r^2. Since the hexagon's area is exactly twice this, its ratio to the circle's area is also exactly twice.