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GeoGebra

Basic rules

Author:Cameron Ualesi, Duane Habecker, Simon Job

Complementary angles

Complementary angles are a pair of angles that add to 90 degrees
You can see in the video that DBA = 68.2 and CBD = 21.8 68.2 + 21.8 = 90 Therefore the angles are complementary
Use the angle tool to find all angles that are complementary

Which angles are complementary?

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  • A
  • B
  • C
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Supplementary angles

Supplementary angles are a pair of angles that add to 180 degrees
You can see in the video that DBA = 75.96 and CBD =104.04 75.96 + 104.04 = 180 Therefore the angles are supplementary

Which pairs of angles are supplementary?

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  • A
  • B
  • C
  • D
  • E
  • F
Check my answer (3)

Angles in a Triangle

All three angles inside a triangle add to 180 degrees
You can see in the video that the three interior angles are: CAB = 27.05 ABC = 114.17 BCA = 38.78 27.05 + 114.17 + 38.78 = 180

Find the missing angle CBA

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  • A
  • B
  • C
  • D
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Use what you have learnt to find EFC

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  • A
  • B
  • C
  • D
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Angles on a line add to 180 degrees

Go to this transum website to have a go: https://www.transum.org/Software/SW/Starter_of_the_day/Students/AnglePoints.asp?Level=2

Angles at a point

Move any point around and watch how the angles change. But what do you notice about the sum of the angles?

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What is the value of FBE?

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  • A
  • B
  • C
Check my answer (3)
For more questions complete this activity: https://www.transum.org/Software/SW/Starter_of_the_day/Students/AnglePoints.asp

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