Free Grade 3 Area of Rectangles in Context Flashcards
Free Grade 3 flashcards for Area of Rectangles 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°.
Free
Core
35 min
24
Learning objectives
Every objective is checkable, and each one maps to an activity and an assessment.
- RememberIdentify area of rectangles in context
Identify area of rectangles in context accurately in a familiar context.
Assessed by: Exit ticket of four short items
- UnderstandExplain area of rectangles in context
Explain area of rectangles in context accurately in a familiar context.
Assessed by: Exit ticket of four short items
- ApplyCalculate area of rectangles in context
Calculate area of rectangles in context accurately in a familiar context.
Assessed by: Exit ticket of four short items
- AnalyseCompare area of rectangles in context
Compare area of rectangles 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 Area of Rectangles 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°.
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 135°. Find the other.[1]
- 2.Two angles on a straight line. One is 41°. Find the other.[1]
- 3.Two angles on a straight line. One is 95°. Find the other.[1]
- 4.Two angles on a straight line. One is 152°. Find the other.[1]
- 5.A triangle has angles 27° and 45°. Find the third angle.[2]
- 6.A triangle has angles 87° and 22°. Find the third angle.[2]
- 7.A triangle has angles 73° and 55°. Find the third angle.[2]
- 8.A triangle has angles 64° and 42°. Find the third angle.[2]
- 9.Find the size of each interior angle of a regular 8-sided polygon.[3]
- 10.Find the size of each interior angle of a regular 6-sided polygon.[3]
- 11.Find the size of each interior angle of a regular 5-sided polygon.[3]
- 12.Find the size of each interior angle of a regular 7-sided polygon.[3]
Show answers and working
1. 45°
Angles on a straight line add to 180°. 180 − 135 = 45°.
2. 139°
Angles on a straight line add to 180°. 180 − 41 = 139°.
3. 85°
Angles on a straight line add to 180°. 180 − 95 = 85°.
4. 28°
Angles on a straight line add to 180°. 180 − 152 = 28°.
5. 108°
Angles in a triangle add to 180°. 180 − 27 − 45 = 108°.
6. 71°
Angles in a triangle add to 180°. 180 − 87 − 22 = 71°.
7. 52°
Angles in a triangle add to 180°. 180 − 73 − 55 = 52°.
8. 74°
Angles in a triangle add to 180°. 180 − 64 − 42 = 74°.
9. 135°
Sum of interior angles = (8 − 2) × 180 = 1080°. Each angle = 1080 ÷ 8 = 135°.
10. 120°
Sum of interior angles = (6 − 2) × 180 = 720°. Each angle = 720 ÷ 6 = 120°.
11. 108°
Sum of interior angles = (5 − 2) × 180 = 540°. Each angle = 540 ÷ 5 = 108°.
12. 128.57°
Sum of interior angles = (7 − 2) × 180 = 900°. Each angle = 900 ÷ 7 = 128.57°.
Worked examples
Two angles on a straight line. One is 100°. Find the other.
- Angles on a straight line add to 180°.
- 180 − 100 = 80°.
- Answer: 80°
A triangle has angles 35° and 59°. Find the third angle.
- Angles in a triangle add to 180°.
- 180 − 35 − 59 = 86°.
- Answer: 86°
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
How mastery is evidenced, and which standards it maps to.
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Frequently asked
- Is this Grade 3 Area of Rectangles 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 Area of Rectangles, Introducing Area of Rectangles, Perimeter of Rectangles. 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 Area of Rectangles in Context?
- Move on to Perimeter of Rectangles, Area of Triangles, Area of Circles, Compound Shapes, which build directly on this idea.
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