rhombus wanted, starting with an isosceles (Greece Junior 2003)
Source:
July 12, 2019
geometryrhombusisosceles
Problem Statement
Let be an isosceles triangle (). The altitude and the perpendiculare bisector of side intersect at point . The perpendicular on line passing through intersects at point . If the circumscribed circle of the triangle intersects line at point , the prove that:
a) .
b) quadrilateral is rhombus.