Angles and lines: types, intersections, circles, bearings and route diagrams are maths skills that are commonly tested in 11+ and Selective School exams in the UK.

## Examples

### Example Question 1:

Which two lines are perpendicular to each other?

**Answer:** A and C

**Explanation:** Perpendicular lines meet at a right angle (90°).

### Example Question 2:

Calculate the angles A, B, C and D.

**Answers:** A = 70°, B = 35°, C = 60°, D = 60°

**Explanation: **All the internal angles in any type of triangle add up to 180°

**A** is in an isosceles triangle with one of the equal angles of 55°. So 55° + 55° = 110° and 180° – 110° = 70°

**B **is in a scalene triangle. 110° + 35° = 145°. So 180° – 145° = 35°

**C** is in an equilateral triangle so all the angles are 60°

**D** is in a right-angled triangle. 90° + 30° = 120°. So 180° – 120° = 60°

### Example Question 3:

Calculate angle Χ

**Answer: **110**°**

**Explanation:** Angle X and the angle of 70° would make a straight line of 180° (co-interior angle). So 180° – 70° = 110°. Or you could spot that angle X is a corresponding angle the same as the angle of 110°.

## Video Tutorials

### Interior Angles in Polygons

### Estimating Angles

### Exterior Angles

### Co-interior Angles

### Corresponding Angles

### Alternate Angles

### Vertically Opposite

### Straight Line

### Around a Point