Math: Geometry Problem 1020: Circle, Tangent, Chord, Perpendicular, Geometric Mean. Level: School, College.

The figure below shows AB and AC tangent to circle O at B and C. D is a point on circle O and DA₁ = a₁, DB₁ = b₁, and DC₁ = c₁ are perpendicular to BC, AC, and AB, respectively. Prove that a₁ is the geometric mean of b₁ and c₁:
  

Geometric Art: Circular Patterns of Problem 1020 using iPad Apps.

Geometric Art using Mobile Apps.

Geometric art is a form of art based on the use and application of geometric figures. A geometric figure is any set or combination of points, lines, surfaces and solids. A mobile app or mobile application software is a computer program designed to run on smartphones and tablet computers.