Let’s solve each triangle one by one. Remember:
the angles in any triangle always add up to 180°. So if we know two angles, we can find the third by subtracting their sum from 180°.
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b)
Angles given: 59° and 70°
Add them: 59 + 70 = 129°
Subtract from 180: 180 - 129 =
51°
→ Missing angle =
51°
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c)
Angles given: 60° and 40°
Add them: 60 + 40 = 100°
Subtract from 180: 180 - 100 =
80°
→ Missing angle =
80°
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d)
Angles given: 75° and 60°
Add them: 75 + 60 = 135°
Subtract from 180: 180 - 135 =
45°
→ Missing angle =
45°
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e)
Angles given: 50° and 75°
Add them: 50 + 75 = 125°
Subtract from 180: 180 - 125 =
55°
→ Missing angle =
55°
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f)
Angles given: 50° and 55°
Add them: 50 + 55 = 105°
Subtract from 180: 180 - 105 =
75°
→ Missing angle =
75°
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Final Answer:
b) 51°
c) 80°
d) 45°
e) 55°
f) 75°
Parent Tip: Review the logic above to help your child master the concept of sum of angles in a triangle worksheet.
