Maths

• arc length

  angle fraction * circumference
• speed

  distance / time
• pressure

  force / area
• density

  mass / volume
• A tangent and a radius meet at 90 degrees
• two radii form an isosceles triangle
• the perpendicular bisector of a chord passes through the centre of the circle
• the angle subtended at the centre of a circle is twice the angle at the circumference from the same two points
• angles in the same segment (drawn from the same chord)are equal
• opposite angles in a cyclical quadrilateral sum to 180
• tangents from the same point are the same length
• alternate segment theorem - the angle between a tangent and a chord is always equal to the angle in the opposite segment
• vertically opposite angles are equal

  
• Alternate angles are equal (Z shape)
• Allied angles sum to 180 (U shape)
• corresponding angles are equal (F shape)