Free Grade 3 Angles Flashcards
Free Grade 3 flashcards for Angles: 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°.
Free
Higher
15 min
24
Learning objectives
Every objective is checkable, and each one maps to an activity and an assessment.
- UnderstandExplain angles
Explain angles accurately in a familiar context.
Assessed by: Exit ticket of four short items
- ApplyCalculate angles
Calculate angles accurately in a familiar context.
Assessed by: Exit ticket of four short items
- AnalyseCompare angles
Compare angles accurately in a familiar context.
Assessed by: Exit ticket of four short items
- EvaluateJustify angles
Justify angles 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 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°.
12 practice questions
Easy to hard, 24 marks in total. Try them first, then open the answers.
- 1.Two angles on a straight line. One is 45°. Find the other.[1]
- 2.Two angles on a straight line. One is 138°. Find the other.[1]
- 3.Two angles on a straight line. One is 52°. Find the other.[1]
- 4.Two angles on a straight line. One is 157°. Find the other.[1]
- 5.A triangle has angles 76° and 20°. Find the third angle.[2]
- 6.A triangle has angles 62° and 40°. Find the third angle.[2]
- 7.A triangle has angles 77° and 31°. Find the third angle.[2]
- 8.A triangle has angles 90° and 20°. Find the third angle.[2]
- 9.Find the size of each interior angle of a regular 6-sided polygon.[3]
- 10.Find the size of each interior angle of a regular 5-sided polygon.[3]
- 11.Find the size of each interior angle of a regular 7-sided polygon.[3]
- 12.Find the size of each interior angle of a regular 9-sided polygon.[3]
Show answers and working
1. 135°
Angles on a straight line add to 180°. 180 − 45 = 135°.
2. 42°
Angles on a straight line add to 180°. 180 − 138 = 42°.
3. 128°
Angles on a straight line add to 180°. 180 − 52 = 128°.
4. 23°
Angles on a straight line add to 180°. 180 − 157 = 23°.
5. 84°
Angles in a triangle add to 180°. 180 − 76 − 20 = 84°.
6. 78°
Angles in a triangle add to 180°. 180 − 62 − 40 = 78°.
7. 72°
Angles in a triangle add to 180°. 180 − 77 − 31 = 72°.
8. 70°
Angles in a triangle add to 180°. 180 − 90 − 20 = 70°.
9. 120°
Sum of interior angles = (6 − 2) × 180 = 720°. Each angle = 720 ÷ 6 = 120°.
10. 108°
Sum of interior angles = (5 − 2) × 180 = 540°. Each angle = 540 ÷ 5 = 108°.
11. 128.57°
Sum of interior angles = (7 − 2) × 180 = 900°. Each angle = 900 ÷ 7 = 128.57°.
12. 140°
Sum of interior angles = (9 − 2) × 180 = 1260°. Each angle = 1260 ÷ 9 = 140°.
Worked examples
Two angles on a straight line. One is 23°. Find the other.
- Angles on a straight line add to 180°.
- 180 − 23 = 157°.
- Answer: 157°
A triangle has angles 43° and 55°. Find the third angle.
- Angles in a triangle add to 180°.
- 180 − 43 − 55 = 82°.
- Answer: 82°
Find the size of each interior angle of a regular 8-sided polygon.
- Sum of interior angles = (8 − 2) × 180 = 1080°.
- Each angle = 1080 ÷ 8 = 135°.
- Answer: 135°
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.
Every free resource for Angles
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Frequently asked
- Is this Grade 3 Angles 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 Algebra. 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?
- Move on to 2D Shapes, Perimeter and Area, 3D Shapes, Transformations, which build directly on this idea.
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