>>13219484Are of a Tri Angle (triangle as you call it) is 1/2 x the basal line x that line which describes the tallness of the figure on the page.
The ratio of the sides of the inner Tri Angle is equivalent to the ratio of the angles of the outer Tri Angle (Pythagoras, de Faggoteria OP, 3000BC). The ratio of the Angles and Sides of the outer triangle is similarly related.
This gives you a relation between the areas of the two Tri Angles. Using Newtons method of Infinitesimal Calculus one can maximize this relation. You will find that this happens when both Tri Angles are equilateral.