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Free Grade 3 Angles in Parallel Lines in Context Flashcards

Free Grade 3 flashcards for Angles in Parallel Lines in Context: 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

35 min

Total marks

24

Learning objectives

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

  • UnderstandExplain angles in parallel lines in context

    Explain angles in parallel lines in context accurately in a familiar context.

    Assessed by: Exit ticket of four short items

  • ApplyCalculate angles in parallel lines in context

    Calculate angles in parallel lines in context accurately in a familiar context.

    Assessed by: Exit ticket of four short items

  • AnalyseCompare angles in parallel lines in context

    Compare angles in parallel lines in context accurately in a familiar context.

    Assessed by: Exit ticket of four short items

  • EvaluateJustify angles in parallel lines in context

    Justify angles in parallel lines in context 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 Angles in Parallel Lines in Context 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 82°. Find the other.[1]
  2. 2.Two angles on a straight line. One is 77°. Find the other.[1]
  3. 3.Two angles on a straight line. One is 105°. Find the other.[1]
  4. 4.Two angles on a straight line. One is 107°. Find the other.[1]
  5. 5.A triangle has angles 24° and 27°. Find the third angle.[2]
  6. 6.A triangle has angles 79° and 25°. Find the third angle.[2]
  7. 7.A triangle has angles 68° and 37°. Find the third angle.[2]
  8. 8.A triangle has angles 46° and 79°. Find the third angle.[2]
  9. 9.Find the size of each interior angle of a regular 7-sided polygon.[3]
  10. 10.Find the size of each interior angle of a regular 5-sided polygon.[3]
  11. 11.Find the size of each interior angle of a regular 10-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. 98°

    Angles on a straight line add to 180°. 180 − 82 = 98°.

  2. 2. 103°

    Angles on a straight line add to 180°. 180 − 77 = 103°.

  3. 3. 75°

    Angles on a straight line add to 180°. 180 − 105 = 75°.

  4. 4. 73°

    Angles on a straight line add to 180°. 180 − 107 = 73°.

  5. 5. 129°

    Angles in a triangle add to 180°. 180 − 24 − 27 = 129°.

  6. 6. 76°

    Angles in a triangle add to 180°. 180 − 79 − 25 = 76°.

  7. 7. 75°

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

  8. 8. 55°

    Angles in a triangle add to 180°. 180 − 46 − 79 = 55°.

  9. 9. 128.57°

    Sum of interior angles = (7 − 2) × 180 = 900°. Each angle = 900 ÷ 7 = 128.57°.

  10. 10. 108°

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

  11. 11. 144°

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

  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 149°. Find the other.

  1. Angles on a straight line add to 180°.
  2. 180 − 149 = 31°.
  3. Answer: 31°
Medium example

A triangle has angles 21° and 46°. Find the third angle.

  1. Angles in a triangle add to 180°.
  2. 180 − 21 − 46 = 113°.
  3. Answer: 113°
Hard example

Find the size of each interior angle of a regular 9-sided polygon.

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

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.

NATIONAL-CURRICULUM NAT-437.1 — Mapped statement covering Angles in Parallel Lines in Context.IB IB-332.2 — Mapped statement covering Angles in Parallel Lines in Context.

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Frequently asked

Is this Grade 3 Angles in Parallel Lines in Context flashcards really free?
Yes. Every flashcards on FreeMathWorksheet is free to use, print and share — no account, no paywall and no watermark.
What should a learner already know before this?
Start with Working with Angles in Parallel Lines, Introducing Angles in Parallel Lines, Vertically Opposite Angles. Each one has its own free lesson, worksheet and quiz.
How is the flashcards 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 Angles in Parallel Lines in Context?
Move on to Angles on a Straight Line, Angles Around a Point, Vertically Opposite Angles, Angles in Polygons, which build directly on this idea.

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