A line extends indefinitely; a ray starts at one point; a segment joins two endpoints. Perpendicular lines meet at 90; parallel lines in a plane never meet. In ABC, B is the vertex. **Object** | **Meaning** Acute, obtuse, reflex angle | Less than 90; between 90 and 180; between 180 and 360 Face, edge, vertex | A surface; a meeting of faces; a meeting of edges Prism | Constant cross-section, with two parallel congruent ends Pyramid | A polygonal base, with triangular faces meeting at one apex A radius joins the centre to the circumference; a diameter is a chord through the centre. A tangent touches the circle at one point. A sector is bounded by two radii and an arc; a segment by a chord and an arc. These names identify which theorem or area formula applies.

A line extends indefinitely; a ray starts at one point; a segment joins two endpoints. Perpendicular lines meet at \(90^\circ\); parallel lines in a plane never meet. In \(\angle ABC\), B is the vertex.

A radius joins the centre to the circumference; a diameter is a chord through the centre. A tangent touches the circle at one point. A sector is bounded by two radii and an arc; a segment by a chord and an arc. These names identify which theorem or area formula applies.

Basic Geometry

Cambridge IGCSE Mathematics 0580. Initial catalogue covers the assessed demands of February/March 2026 Paper 22; further Core and Extended mappings require paper-level scope review.

Lines, angles and solid geometry

Lines, angles and solid geometry

Object	Meaning
Acute, obtuse, reflex angle	Less than \(90^\circ\); between \(90^\circ\) and \(180^\circ\); between \(180^\circ\) and \(360^\circ\)
Face, edge, vertex	A surface; a meeting of faces; a meeting of edges
Prism	Constant cross-section, with two parallel congruent ends
Pyramid	A polygonal base, with triangular faces meeting at one apex