Khan Academy on a Stick : Problem involving angle derived from square and circle

Khan Academy on a Stick

Congruence and isosceles and equilateral triangles

Congruent legs and base angles of Isosceles Triangles
Equilateral Triangle Sides and Angles Congruent
Equilateral and Isosceles Example Problems
Another Isosceles Example Problem
Example involving an isosceles triangle and parallel lines
Figuring out all the angles for congruent triangles example
Problem involving angle derived from square and circle

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