Question

In Fig., AC ⊥ CE and ∠A : ∠B :∠C = 3:2:1, find the value of ∠ECD.

Answer 1

Given,

AC is perpendicular to CE

∠A: ∠B: ∠C = 3: 2: 1

Let,

∠A = 3k

∠B = 2k

∠C = k

∠A + ∠B + ∠C = 180°

3k + 2k + k = 180°

6k = 180°

k = 30°

Therefore,

∠A = 3k = 90°

∠B = 2k = 60°

∠C = k = 30°

Now,

∠C + ∠ACE + ∠ECD = 180°(Linear pair)

30° + 90° + ∠ECD = 180°

∠ECD = 180° – 120°

= 60°