A flower - solution |
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First I notice that the distance between the tips of the petals is one radius, let's call the radius r.
If we use x to denote the height of the triangle formed by that line and the two radii connecting it to the center, then by the Pythagorean theorem we get:
x² + r²/4 = r²
x² = 3 × r²/4
x = (r/2) × √3
Let As be the area of the sector and At be the area of the triangle:
As = r² × π/6
At = x × r/2
We put in our expression for x into this and get:
At = (r/2) × (√3) × r/2
At = (r²/4) × √3
Let Ah be the area of half a petal. And note that half a petal is also found between the triangle and the circumference of the circle. Therefore:
Ah = As - At
Ah = r² × π/6 - (r²/4) × √3
Ah = r² × (π/6 - (1/4) × √3)
We have 12 half petals, so:
Aflower = 12 × Ah
Aflower = 12 × r² × (π/6 - (1/4) × √3)
Aflower = r² × (2 × π - 3 × √3)
Aflower = r² × (2 × π - √27)