MathDB
Area of region enclosed by tangents of 3 concentric circles

Source:

January 30, 2011
geometrytrigonometrygeometry unsolved

Problem Statement

Three concentric circles with common center OO are cut by a common chord in successive points A,B,CA, B, C. Tangents drawn to the circles at the points A,B,CA, B, C enclose a triangular region. If the distance from point OO to the common chord is equal to pp, prove that the area of the region enclosed by the tangents is equal to AB⋅BC⋅CA2p\frac{AB \cdot BC \cdot CA}{2p}
Back to ProblemsView on AoPS