MathDB

1

Part of 2000 India Regional Mathematical Olympiad

Problems(1)

Prove an eq triangle

Source: Indian RMO 2000 Problem 1

10/26/2005
Let ACAC be a line segment in the plane and BB a points between AA and CC. Construct isosceles triangles PABPAB and QACQAC on one side of the segment ACAC such that ∠APB=∠BQC=120∘\angle APB = \angle BQC = 120^{\circ} and an isosceles triangle RACRAC on the other side of ACAC such that ∠ARC=120∘.\angle ARC = 120^{\circ}. Show that PQRPQR is an equilateral triangle.
analytic geometryparallelogramIBO 2k14