The alternate segment theorem, is also known as the tangent-chord theorem. It is one of the circle theorems which states that the angle between a chord and a tangent through one of the chord's endpoints is equal to the angle in the alternate segment of the chord. The theorem is used to find missing angle and arc measurements. According to the alternate segment theorem, angle [katex] ABC [/katex] is equal to angle [katex] EAC [/katex] and angle [katex] BCA [/katex] is equal to angle [katex] BAD. [/katex]