# Geometry Problem 2: Proving Angle Measures in a Triangle with Congruent angles and Known Degree Measures, 10, 20, and 30 degrees. Level: High School, College, Math Education

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In triangle ABC, it is given that angle BAO is congruent to angle OAC and both measure 20 degrees, angle ACO measures 10 degrees, and angle OCB measures 30 degrees. Prove that angle OBC measures 80 degrees using elementary geometry, such as Euclid's Elements.

Geometry Problem 2

Amidst the angles set in triad,
BAO and OAC meet at 20 they said,
Ten degrees ACO owns,
While OCB has 30 degrees shown,
Prove now, OBC measures eighty, and let it be laid.

## Art of Geometry Problem 2 using Mobile Apps. Circle Patterns.

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. See also the kaleidoscope of problem 2.