PracticeQuestionsYears 1–7
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Angles and geometric properties

Year 6 · Upper Key Stage 2 · 6G4 — Find unknown angles in triangles, quadrilaterals and on lines

Draft — awaiting teacher review

I

Concept Anchor

Angles on a straight line sum to 180∘180^\circ. Angles in a triangle sum to 180∘180^\circ. Angles around a point sum to 360∘360^\circ.

Worked example

A triangle has angles 48∘48^\circ and 67∘67^\circ. Find the third.

  1. 1.Add the known angles: 48+67=11548 + 67 = 115.
  2. 2.Subtract from 180: 180−115=65180 - 115 = 65.
  3. 3.Third angle =65∘= 65^\circ.
II

Guided Check

An isosceles triangle has a top angle of 40∘40^\circ. What is each base angle?

    III

    Independent Diagnostic Practice

    Q1Year 66G4 — Find unknown angles·Fluency·●○○Draft — awaiting teacher review

    Two angles on a straight line. One is 125∘125^\circ. What is the other?

    Q2Year 66G4 — Angles in quadrilaterals·Reasoning·●●○Draft — awaiting teacher review

    A quadrilateral has angles 90∘90^\circ, 110∘110^\circ and 70∘70^\circ. Find the fourth.

    Q3Year 66G3 — Area of triangles·Problem Solving·●●○Draft — awaiting teacher review

    A triangular sign has base 10 cm and perpendicular height 6 cm. How much surface needs painting on one side?