Free Grade 3 Introducing Triangles Techniques Quizzes
Free Grade 3 quizzes for Introducing Triangles Techniques: 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
Core
30 min
24
Learning objectives
Every objective is checkable, and each one maps to an activity and an assessment.
- RememberIdentify introducing triangles techniques
Identify introducing triangles techniques accurately in a familiar context.
Assessed by: Exit ticket of four short items
- UnderstandExplain introducing triangles techniques
Explain introducing triangles techniques accurately in a familiar context.
Assessed by: Exit ticket of four short items
- ApplyCalculate introducing triangles techniques
Calculate introducing triangles techniques accurately in a familiar context.
Assessed by: Exit ticket of four short items
- AnalyseCompare introducing triangles techniques
Compare introducing triangles techniques 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 Triangles Techniques 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 76°. Find the other.[1]
- 2.Two angles on a straight line. One is 159°. Find the other.[1]
- 3.Two angles on a straight line. One is 68°. Find the other.[1]
- 4.Two angles on a straight line. One is 92°. Find the other.[1]
- 5.A triangle has angles 71° and 53°. Find the third angle.[2]
- 6.A triangle has angles 33° and 76°. Find the third angle.[2]
- 7.A triangle has angles 45° and 32°. Find the third angle.[2]
- 8.A triangle has angles 77° and 68°. 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 7-sided polygon.[3]
- 11.Find the size of each interior angle of a regular 8-sided polygon.[3]
- 12.Find the size of each interior angle of a regular 9-sided polygon.[3]
Show answers and working
1. 104°
Angles on a straight line add to 180°. 180 − 76 = 104°.
2. 21°
Angles on a straight line add to 180°. 180 − 159 = 21°.
3. 112°
Angles on a straight line add to 180°. 180 − 68 = 112°.
4. 88°
Angles on a straight line add to 180°. 180 − 92 = 88°.
5. 56°
Angles in a triangle add to 180°. 180 − 71 − 53 = 56°.
6. 71°
Angles in a triangle add to 180°. 180 − 33 − 76 = 71°.
7. 103°
Angles in a triangle add to 180°. 180 − 45 − 32 = 103°.
8. 35°
Angles in a triangle add to 180°. 180 − 77 − 68 = 35°.
9. 120°
Sum of interior angles = (6 − 2) × 180 = 720°. Each angle = 720 ÷ 6 = 120°.
10. 128.57°
Sum of interior angles = (7 − 2) × 180 = 900°. Each angle = 900 ÷ 7 = 128.57°.
11. 135°
Sum of interior angles = (8 − 2) × 180 = 1080°. Each angle = 1080 ÷ 8 = 135°.
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 160°. Find the other.
- Angles on a straight line add to 180°.
- 180 − 160 = 20°.
- Answer: 20°
A triangle has angles 42° and 78°. Find the third angle.
- Angles in a triangle add to 180°.
- 180 − 42 − 78 = 60°.
- Answer: 60°
Find the size of each interior angle of a regular 5-sided polygon.
- Sum of interior angles = (5 − 2) × 180 = 540°.
- Each angle = 540 ÷ 5 = 108°.
- 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.
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Frequently asked
- Is this Grade 3 Introducing Triangles Techniques quiz really free?
- Yes. Every quizzes 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 Introducing Triangles Essentials, Angles. Each one has its own free lesson, worksheet and quiz.
- How is the quiz 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 Triangles Techniques?
- Move on to Introducing Triangles Word Problems, Introducing Triangles Common Errors, Working with Triangles, Triangles in Context, which build directly on this idea.
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