circum-ellipse

A circumellipse is a circumconic of a triangle that is an ellipse. There is an amazing formula for the area of a circumellipse. Let d_A be the length of the chord of the ellipse through the center of the ellipse and parallel to the sideline B C of the reference triangle Δ A B C, and similarly define d_B and d_C.

circle | circumconic | excentral-hexyl ellipse | Hofstadter ellipse | inellipse | Macbeath circumconic | Steiner circumellipse