Edexcel IGCSE Math A 4.1 angles lines and triangles

Use this angles topic to identify angle types, calculate unknown angles and justify results using line, triangle and isosceles properties.

Exam points

Identify acute, obtuse, reflex and right angles from diagrams or marked shapes.
Calculate unknown angles using straight lines, parallel lines and intersecting lines.
Use triangle angle sums, exterior angles and isosceles properties to find values.

Covered syllabus points

4.1.A Distinguish between acute, obtuse, reflex and right 4.1.B Angle properties of intersecting lines, parallel lines 4.1.C The exterior angle of a triangle property and the angle 4.1.D The terms ‘isosceles’, ‘equilateral’ and ‘right-angled

[Maximum number: 1]

What type of angle is the angle marked x ?

Figure for Question 4.1 Angles, lines and triangles question 1 — Edexcel IGCSE Math A Foundation

[Maximum number: 4]

Diagram NOT accurately drawn

ABC is a straight line.

(a)

Work out the value of x

[ 1 ]

(b)

Work out the value of y

You must show your working.

[ 3 ]

$\frac{180}{3}=60$ 360-(105+125+60)=70

Final answer:
70

Marking guidance:
- M1 for an angle of $60^\circ$ in the triangle
- M1 for a correct complete method
- A1 for 70

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Covered syllabus points

4.1 Angles, lines and triangles question 1

4.1 Angles, lines and triangles question 2

Question (a)

Question (b)