Circle Theorems
Angles in shapes, questions on circles answered
0:00 Angles on straight line
0:30 Angle sum in triangle & quadrilateral
1:07 Vertically opposite angles
1:33 Alternate angles
1:54 Corresponding angles
2:24 Tangent & radius perpendicular
3:03 2 tangents from 1 point make congruent triangles
3:57 Isosceles triangles in circles
4:48 Perpendicular bisector of chord passes through centre
5:43 Angle at centre double angle on circumference
7:00 Angle in semicircle is right-angle
7:32 Angles on circumference
8:40 Cyclic quadrilateral: opposite angles sum to 180
9:43 Alternate segment theorem
11:50 Answered questions