Basic rules

Complementary angles

Complementary angles are a pair of angles that add to 90 degrees

You can see in the video that [math]\angle[/math]DBA = 68.2 and [math]\angle[/math]CBD = 21.8[br]68.2 + 21.8 = 90[br]Therefore the angles are [b]complementary[/b]

Use the angle tool to find all angles that are complementary

Which angles are complementary?[br]

[math]\angle[/math]CBD and [math]\angle[/math]DBA [math]\angle[/math]ABE and [math]\angle[/math]CBD [math]\angle[/math]ABE and [math]\angle[/math]DBA

Supplementary angles

Supplementary angles are a pair of angles that add to 180 degrees

You can see in the video that [math]\angle[/math]DBA = 75.96 and [math]\angle[/math]CBD =104.04[br]75.96 + 104.04 = 180[br]Therefore the angles are [b]supplementary[/b]

Which pairs of angles are supplementary?

[math]\angle[/math]MYD and [math]\angle[/math]CYF [math]\angle[/math]WYD and [math]\angle[/math]WYF [math]\angle[/math]MYF and [math]\angle[/math]CYF [math]\angle[/math]MYW and [math]\angle[/math]CYW [math]\angle[/math]CYF and [math]\angle[/math]MYD [math]\angle[/math]DYC and [math]\angle[/math]MYD

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:[br][math]\angle[/math]CAB = 27.05[math]^\circ[/math][br][math]\angle[/math]ABC = 114.17[math]^\circ[/math][br][math]\angle[/math]BCA = 38.78[math]^\circ[/math][br][br]27.05 + 114.17 + 38.78 = 180

Find the missing angle [math]\angle[/math]CBA

54.13[math]^\circ[/math] 94.98[math]^\circ[/math] 44.17[math]^\circ[/math] 125.87[math]^\circ[/math]

Use what you have learnt to find [math]\angle[/math]EFC

80.094[math]^\circ[/math] 99.96[math]^\circ[/math] 38.66 90[math]^\circ[/math]

Angles on a line add to 180 degrees

Go to this transum website to have a go:[br]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.[br]But what do you notice about the sum of the angles?

What is the value of [math]\angle[/math]FBE?

287.99[math]^\circ[/math] 42.62[math]^\circ[/math] 72.01[math]^{\circ}[/math]

For more questions complete this activity:[br]https://www.transum.org/Software/SW/Starter_of_the_day/Students/AnglePoints.asp