Angles on a straight line, round a point, vertically opposite and in triangles, including equations in x.
What you will learn
- Use angles on a line (180°) and round a point (360°)
- Use vertically opposite angles
- Use the angle sum of a triangle and isosceles triangles
Types of angle
Angles are measured in degrees (°).
A full turn is 360°.
- An acute angle is less than 90°.
- A right angle is exactly 90°, marked with a small square.
- An obtuse angle is between 90° and 180°.
- A reflex angle is between 180° and 360°.
So 40° is acute, 135° is obtuse and 250° is reflex.
The rest of this lesson and its 7 practice questions are locked.
In this lesson
- Types of angle
- The facts
- Angles with x
7 practice questions, marked as you go; about 20 minutes in all.
Key terms
Acute, Right angle, Obtuse, Reflex, Equal
In this unit: Angles, polygons and parallel lines
Angle facts on lines, at points and in triangles, angles with parallel lines, quadrilaterals, interior and exterior angles of polygons, and chains of reasoning.