More simply, opposite angles in a cyclic quadrilateral add up to 180°. A tangent is a straight line which touches the circle at a point but does not cut through the circle. There are two theorems ...

Circle theorems - Higher - Edexcel Circles have different angle properties described by different circle theorems. Circle theorems are used in geometric proofs and to calculate angles ...

The activities focus on spatial reasoning and geometry, which are often taught during the last few months of the school year, and which provide important foundations for mathematics reasoning more ...