In ∆ ABC, AC = BC and ∠ABC = 50°, the side BC

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In ∆ ABC, AC = BC and ∠ABC = 50°, the side BC is produced to D so that BC = CD then the value of ∠BAD is

1. 80°
2. 40°
3. 90°
4. 50°

Correct Option: C

We draw a figure triangle ABC whose the side BC is produced to D so that BC = CD ,

Given , AC = BC and ∠ABC = ∠BAC = 50°
∴ ∠ACB = 180° – 100° = 80°
∴ ∠ACD = 180° – 80° = 100

∠CAD = ∠CDA =	80°	= 40°
	2

∴ ∠BAD = ∠BAC + ∠CAD
∠BAD = 50° + 40° = 90°