Free Grade 3 Introducing Angle Bisector Techniques Flashcards
Free Grade 3 flashcards for Introducing Angle Bisector 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
Foundation
35 min
24
Learning objectives
Every objective is checkable, and each one maps to an activity and an assessment.
- UnderstandExplain introducing angle bisector techniques
Explain introducing angle bisector techniques accurately in a familiar context.
Assessed by: Exit ticket of four short items
- ApplyCalculate introducing angle bisector techniques
Calculate introducing angle bisector techniques accurately in a familiar context.
Assessed by: Exit ticket of four short items
- AnalyseCompare introducing angle bisector techniques
Compare introducing angle bisector techniques accurately in a familiar context.
Assessed by: Exit ticket of four short items
- EvaluateJustify introducing angle bisector techniques
Justify introducing angle bisector 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 Angle Bisector 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 57°. Find the other.[1]
- 2.Two angles on a straight line. One is 76°. Find the other.[1]
- 3.Two angles on a straight line. One is 72°. Find the other.[1]
- 4.Two angles on a straight line. One is 70°. Find the other.[1]
- 5.A triangle has angles 28° and 25°. Find the third angle.[2]
- 6.A triangle has angles 40° and 112°. Find the third angle.[2]
- 7.A triangle has angles 35° and 108°. Find the third angle.[2]
- 8.A triangle has angles 36° and 65°. Find the third angle.[2]
- 9.Find the size of each interior angle of a regular 9-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 5-sided polygon.[3]
Show answers and working
1. 123°
Angles on a straight line add to 180°. 180 − 57 = 123°.
2. 104°
Angles on a straight line add to 180°. 180 − 76 = 104°.
3. 108°
Angles on a straight line add to 180°. 180 − 72 = 108°.
4. 110°
Angles on a straight line add to 180°. 180 − 70 = 110°.
5. 127°
Angles in a triangle add to 180°. 180 − 28 − 25 = 127°.
6. 28°
Angles in a triangle add to 180°. 180 − 40 − 112 = 28°.
7. 37°
Angles in a triangle add to 180°. 180 − 35 − 108 = 37°.
8. 79°
Angles in a triangle add to 180°. 180 − 36 − 65 = 79°.
9. 140°
Sum of interior angles = (9 − 2) × 180 = 1260°. Each angle = 1260 ÷ 9 = 140°.
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. 108°
Sum of interior angles = (5 − 2) × 180 = 540°. Each angle = 540 ÷ 5 = 108°.
Worked examples
Two angles on a straight line. One is 104°. Find the other.
- Angles on a straight line add to 180°.
- 180 − 104 = 76°.
- Answer: 76°
A triangle has angles 89° and 29°. Find the third angle.
- Angles in a triangle add to 180°.
- 180 − 89 − 29 = 62°.
- Answer: 62°
Find the size of each interior angle of a regular 10-sided polygon.
- Sum of interior angles = (10 − 2) × 180 = 1440°.
- Each angle = 1440 ÷ 10 = 144°.
- Answer: 144°
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
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Frequently asked
- Is this Grade 3 Introducing Angle Bisector Techniques 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 Introducing Angle Bisector Essentials, Perpendicular Bisector. 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 Introducing Angle Bisector Techniques?
- Move on to Introducing Angle Bisector Word Problems, Introducing Angle Bisector Common Errors, Working with Angle Bisector, Angle Bisector in Context, which build directly on this idea.
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