Answer:
A) ∠9 = ∠10 = ∠11 = ∠12 = 90°
∠2 = ∠3 = ∠5 = ∠8 = 135°
∠1 = ∠4 = ∠6 = ∠7 = 45°
B) 1. ∠4 and ∠1 -> vertical angles
2. ∠7 and ∠5 -> supplementary
3. ∠9 and ∠10 -> supplementary
Step-by-step explanation:
<u>Data</u>
The following are vertical angles, so they are congruent:
∠1 ≅ ∠4
∠3 ≅ ∠2
∠11 ≅ ∠9
∠10 ≅ ∠12
∠7 ≅ ∠6
∠5 ≅ ∠8
From here and data, it is deduced that
∠11 ≅ ∠9 ≅ ∠10 ≅ ∠12
From the picture, the addition of them is equal to 360°, then:
∠11 + ∠9 + ∠10 + ∠12 = 360°
4*∠11 = 360°
∠11 = 360°/4
∠11 = 90° = ∠10 = ∠9 = ∠12
∠2 and ∠4 are supplementary, then:
∠2 + ∠4 = 180°
∠2 = 180° - 45°
∠2 = 135°
∠7 and ∠5 are supplementary, then:
∠7 + ∠5 = 180°
∠7 = 180° - 135°
∠7 = 45°
