Let’s solve each problem one by one. We’ll use the fact that:
- The sum of angles in a
triangle is always
180°.
- The sum of angles in a
quadrilateral (4-sided shape) is always
360°.
We’ll find angle b for each figure using these rules.
---
Problem 1:
Triangle with angles: 75°, 25°, and b
Sum = 180°
So, b = 180 - 75 - 25 =
80°
✔ Check: 75 + 25 + 80 = 180 → Correct
---
Problem 2:
Triangle with angles: 90°, 35°, and b
Sum = 180°
b = 180 - 90 - 35 =
55°
✔ Check: 90 + 35 + 55 = 180 → Correct
---
Problem 3:
Triangle with angles: 100°, 30°, and b
Sum = 180°
b = 180 - 100 - 30 =
50°
✔ Check: 100 + 30 + 50 = 180 → Correct
---
Problem 4:
Triangle with angles: 120°, 25°, and b
Sum = 180°
b = 180 - 120 - 25 =
35°
✔ Check: 120 + 25 + 35 = 180 → Correct
---
Problem 5:
Quadrilateral with angles: 90°, 90°, 110°, and b
Sum = 360°
b = 360 - 90 - 90 - 110 =
70°
✔ Check: 90 + 90 + 110 + 70 = 360 → Correct
---
Problem 6:
Quadrilateral with angles: 90°, 90°, 100°, and b
Sum = 360°
b = 360 - 90 - 90 - 100 =
80°
✔ Check: 90 + 90 + 100 + 80 = 360 → Correct
---
Problem 7:
Quadrilateral with angles: 90°, 90°, 120°, and b
Sum = 360°
b = 360 - 90 - 90 - 120 =
60°
✔ Check: 90 + 90 + 120 + 60 = 360 → Correct
---
Problem 8:
Quadrilateral with angles: 90°, 90°, 110°, and b
Sum = 360°
b = 360 - 90 - 90 - 110 =
70°
✔ Check: 90 + 90 + 110 + 70 = 360 → Correct
---
Final Answer:
1. 80°
2. 55°
3. 50°
4. 35°
5. 70°
6. 80°
7. 60°
8. 70°
Parent Tip: Review the logic above to help your child master the concept of missing angles in quadrilaterals worksheet.
