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Aptitude · Q40

Geometry

Competitive Exams · Aptitude · question 40

Q40

In ΔABC, D is a point on BC such that ∠ADB = 2∠DAC, ∠BAC = 70° and ∠B = 56°. What is the measure of ∠ADC?

A.
54°
B.
81°
C.
74°
D.
72°
Answer

Answer: Option D

Solution

Answer: Option D
Solution:
Geometry mcq question image
Let ∠DAC = x
∠ADB = 2x
∠ACD + ∠DAC = ∠ADB
∠ACD + x = 2x
∠ACD = 2x - x = x
In ΔABC
∠A + ∠B + ∠C = 180°
70° + 56° + ∠C = 180°
∠C = 54°
∠ADC = 180° - 2x
= 180° - 2 × 54°
= 180° - 108°
= 72°