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Answer:
m∠1 +m∠8 = 90°
Step-by-step explanation:
There is no necessary sum relation between angles 3 and 5 or angles 7 and 10. The only thing you can say about those angle pairs is ...
∠3 + 90° = ∠5
∠10 +90° = ∠7
Angles 8 and 9 are congruent, so don't have any necessary sum.
Angle 1 is congruent with angle 3, which is complementary to angle 8, so we must have ...
m∠1 +m∠8 = 90°
