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Free Grade 3 Introducing Vertically Opposite Angles Essentials Worksheets

Free Grade 3 worksheets for Introducing Vertically Opposite Angles Essentials: 12 real questions with a full answer key and worked solutions. Angles on a straight line add to 180°, around a point to 360°, and inside a triangle to 180°. A polygon with n sides has interior angles adding to (n − 2) × 180°.

Price

Free

Difficulty

Foundation

Estimated time

15 min

Total marks

24

Learning objectives

Every objective is checkable, and each one maps to an activity and an assessment.

  • RememberIdentify introducing vertically opposite angles essentials

    Identify introducing vertically opposite angles essentials accurately in a familiar context.

    Assessed by: Exit ticket of four short items

  • UnderstandExplain introducing vertically opposite angles essentials

    Explain introducing vertically opposite angles essentials accurately in a familiar context.

    Assessed by: Exit ticket of four short items

  • ApplyCalculate introducing vertically opposite angles essentials

    Calculate introducing vertically opposite angles essentials accurately in a familiar context.

    Assessed by: Exit ticket of four short items

  • AnalyseCompare introducing vertically opposite angles essentials

    Compare introducing vertically opposite angles essentials accurately in a familiar context.

    Assessed by: Exit ticket of four short items

Prerequisites

Close these gaps first — each has its own free lesson, worksheet and quiz.

How Introducing Vertically Opposite Angles Essentials works

Angles on a straight line add to 180°, around a point to 360°, and inside a triangle to 180°. A polygon with n sides has interior angles adding to (n − 2) × 180°.

Key wordsdegreeacuteobtusereflexinterior angle

12 practice questions

Easy to hard, 24 marks in total. Try them first, then open the answers.

  1. 1.Two angles on a straight line. One is 99°. Find the other.[1]
  2. 2.Two angles on a straight line. One is 137°. Find the other.[1]
  3. 3.Two angles on a straight line. One is 30°. Find the other.[1]
  4. 4.Two angles on a straight line. One is 141°. Find the other.[1]
  5. 5.A triangle has angles 33° and 120°. Find the third angle.[2]
  6. 6.A triangle has angles 60° and 82°. Find the third angle.[2]
  7. 7.A triangle has angles 90° and 53°. Find the third angle.[2]
  8. 8.A triangle has angles 75° and 37°. Find the third angle.[2]
  9. 9.Find the size of each interior angle of a regular 10-sided polygon.[3]
  10. 10.Find the size of each interior angle of a regular 8-sided polygon.[3]
  11. 11.Find the size of each interior angle of a regular 9-sided polygon.[3]
  12. 12.Find the size of each interior angle of a regular 6-sided polygon.[3]
Show answers and working
  1. 1. 81°

    Angles on a straight line add to 180°. 180 − 99 = 81°.

  2. 2. 43°

    Angles on a straight line add to 180°. 180 − 137 = 43°.

  3. 3. 150°

    Angles on a straight line add to 180°. 180 − 30 = 150°.

  4. 4. 39°

    Angles on a straight line add to 180°. 180 − 141 = 39°.

  5. 5. 27°

    Angles in a triangle add to 180°. 180 − 33 − 120 = 27°.

  6. 6. 38°

    Angles in a triangle add to 180°. 180 − 60 − 82 = 38°.

  7. 7. 37°

    Angles in a triangle add to 180°. 180 − 90 − 53 = 37°.

  8. 8. 68°

    Angles in a triangle add to 180°. 180 − 75 − 37 = 68°.

  9. 9. 144°

    Sum of interior angles = (10 − 2) × 180 = 1440°. Each angle = 1440 ÷ 10 = 144°.

  10. 10. 135°

    Sum of interior angles = (8 − 2) × 180 = 1080°. Each angle = 1080 ÷ 8 = 135°.

  11. 11. 140°

    Sum of interior angles = (9 − 2) × 180 = 1260°. Each angle = 1260 ÷ 9 = 140°.

  12. 12. 120°

    Sum of interior angles = (6 − 2) × 180 = 720°. Each angle = 720 ÷ 6 = 120°.

Worked examples

Easy example

Two angles on a straight line. One is 97°. Find the other.

  1. Angles on a straight line add to 180°.
  2. 180 − 97 = 83°.
  3. Answer: 83°
Medium example

A triangle has angles 47° and 33°. Find the third angle.

  1. Angles in a triangle add to 180°.
  2. 180 − 47 − 33 = 100°.
  3. Answer: 100°
Hard example

Find the size of each interior angle of a regular 5-sided polygon.

  1. Sum of interior angles = (5 − 2) × 180 = 540°.
  2. Each angle = 540 ÷ 5 = 108°.
  3. Answer: 108°

Interactive practice

Free, no account required — answer on screen or print it.

Common mistakes

What learners typically get wrong, and how to fix it.

  • Reads the wrong scale on a protractor.

    Correction: Start from the 0 on the arm you are measuring from.

  • Uses 360° for a triangle.

    Correction: Triangle = 180°, quadrilateral = 360°.

Teacher tips

  • · Estimate the angle type before measuring.

Parent tips

  • · Spot right angles around the house.

Real-life applications

  • · Ramps, clock hands, building and design.

Assessment objectives

How mastery is evidenced, and which standards it maps to.

AQA AQA-579.1 — Mapped statement covering Introducing Vertically Opposite Angles Essentials.FBISE FBI-383.2 — Mapped statement covering Introducing Vertically Opposite Angles Essentials.

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Frequently asked

Is this Grade 3 Introducing Vertically Opposite Angles Essentials worksheet really free?
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What should a learner already know before this?
Start with Angles Around a Point. Each one has its own free lesson, worksheet and quiz.
How is the worksheet sequenced?
Recognition first, then understanding, application, reasoning and finally mastery — the same ladder used across every free resource on the platform.
What comes next after Introducing Vertically Opposite Angles Essentials?
Move on to Introducing Vertically Opposite Angles Techniques, Introducing Vertically Opposite Angles Word Problems, Introducing Vertically Opposite Angles Common Errors, Working with Vertically Opposite Angles, which build directly on this idea.

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