MathDB
semicircles on sides of a cyclic quadrilateral with perpendicular diagonals

Source: Lusophon 2012 CPLP P6

August 29, 2018
geometrycyclic quadrilateralperpendiculardiagonals

Problem Statement

A quadrilateral ABCDABCD is inscribed in a circle of center OO. It is known that the diagonals ACAC and BDBD are perpendicular. On each side we build semicircles, externally, as shown in the figure. a) Show that the triangles AOBAOB and CODCOD have the equal areas. b) If AC=8AC=8 cm and BD=6BD= 6 cm, determine the area of the shaded region.