141 Circumcircle of a trangle with its circumcenter outside the triangle

140 Circumcircle of a trangle with its circumcenter inside the triangle

139 Proof of the Inscribed Angle Theorem - the vertex of central angle is outside a inscribed angle

138 The Inscribed Angle Theorem proof - the vertex of central angle is between the two arms of a inscribed angle

137 The Inscribed Angle Theorem proof - the vertex of central angle is on one arm of a inscribed angle

136 The vertex of central angle is outside a inscribed angle

135 The vertex of central angle is between the two arms of a inscribed angle

134 The vertex of central angle is on one arm of a inscribed angle

133 Rectangles for proof of Difference of Squares Formula

132 A right trangle geometric shape

131 An obtuse angle triangle with one of interior angles larger than 90 degrees

130 An acute angle triangle with interior angles less than 90 degrees