Geometry & Angles

Geometry questions are a major part of the GL 11+ exam. You need to know the properties of 2D shapes, understand angle rules, and be able to identify different types of triangles and quadrilaterals. This lesson covers the key facts and techniques.

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Types of Angles

Type of angle	Size	Diagram hint
Acute	Less than 90°	Small and sharp
Right angle	Exactly 90°	Square corner
Obtuse	Between 90° and 180°	Wide opening
Straight line	Exactly 180°	Flat line
Reflex	Between 180° and 360°	More than a half turn
Full turn	Exactly 360°	Complete circle

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Angle Rules

Angles on a Straight Line

Angles on a straight line add up to 180°.

Worked Example: Two angles on a straight line are 115° and x°. Find x.

• 115 + x = 180
• x = 180 - 115 = 65°

Angles at a Point

Angles around a point add up to 360°.