GCSE Mathematics (9-1)
    All books

    16.1 Angle facts at a point and on a line — Practise with help

    Try each question before opening a hint. Open the next part only when you need it.

    Warm-up: remember

    1. Work out 180−73180-73.
    2. Name the angle fact for opposite angles where two lines cross.
    Check your answers
    1. 107∘107^\circ. 2. Vertically opposite angles are equal.

    Practise with help

    1. Angles x∘x^\circ and 124∘124^\circ lie on a straight line. Find xx.

    Hint

    Write the angle fact that fits the diagram or shape.

    One step

    Set up an equation using the straight-line angle total.

    Full working

    Angles on a straight line total 180∘180^\circ.

    x+124=180x+124=180 x=180−124=56∘x=180-124=56^\circ

    2. Three angles around a point are 85∘85^\circ, 140∘140^\circ and y∘y^\circ. Find yy.

    Hint

    Mark the known angles and identify their relationship before calculating.

    One step

    Angles around a point total 360∘360^\circ. Write an equation with that total.

    Full working

    Angles around a point total 360∘360^\circ.

    85+140+y=36085+140+y=360 y=360−85−140=135∘y=360-85-140=135^\circ

    3. Earlier learning. Work out: 7+5×37+5\times3. Explain which operation you do first.

    Hint

    Use the order of operations.

    One step

    Calculate 5×35\times3 before adding.

    Full working

    7+5×3=7+15=227+5\times3=7+15=22. Multiplication comes before addition.

    Settings

    Colour scheme

    Applies to every book you read here.

    Reading theme

    Applies to every book you read here.