Area of a Triangle inside the Incircle
Area of a Triangle inside the Incircle
Let ABC be a triangle, the radius of its incircle, and the radius of its circumcircle. Let D and E be the feet of the perpendiculars drawn from the center I of the incircle onto AB and AC, respectively. Then the area of the triangle IDE is .
r
R
BC×/(4R)
2
r