Geometry
posted by Sam on .
My class is learning about the areas of regular polygons and circles and I'm so confused. How are you supposed to figue out the area a regular triangle inscribed in a circle when all you know is that the radius of the circle is 1.5?

If it is a rt triangle occupying less
that i/2 of the circle:
At = 2As,
As = At/2.
At = Area of the triangle.
As = A shaded area between triangle and
circle.
At + As = pi*r^2/2 = 1/2 of a circle.
Substitute At/2 for As:
At + At/2 = 3.14*(1.5)^2/2,
1.5At = 3.53,
At = 2.36. = Area of triangle.