Answer:
m∠ACE = 90°
Step-by-step explanation:
Figure Interpretation:
m∠CBA + m∠CDE = 180
m∠BCA = (180-m∠CBA)/2
m∠DCE = (180-m∠CDE)/2
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Then
m∠BCA + m∠DCE = (180-m∠CBA)/2 + (180-m∠CDE)/2
= [360-(m∠CBA+m∠CDE)]/2
= [360 - 180]/2
= 90
finally,
m∠ACE= 180 - (m∠BCA + m∠DCE)
= 180 - 90
= 90
