In the figure, AC is perpendicular to CE and ∠A: ∠B: ∠C = 3:2:1, the measure of ∠ECD is
60o
Let the angles be 3x, 2x, x
By angle sum property of a triangle you get
x= 30o
Hence ÐA = 90o, ÐB = 60o and ÐACB =30o.
Now, ÐACB + ÐACE + ÐECD = 180o (Angles on a straight line)
ÐECD = 60o