Q19 of 153 Page 144

In the given figure, AD divides in the ratio 1:3 and AD=DB. Determine the value of.

X=90


Explanation:


∠BAC + ∠CAE = 180°[Because BE is a straight line]


⇒ ∠BAC + 108° = 180°


⇒ ∠BAC = 72°


Now,
AD = DB


=


∠BAD = ( �)72°= 18°


∠DAC = ( �)72°= 54°


In triangle ABC,


∠A + ∠B + ∠C = 180°[Sum of angles of triangle]


⇒ 72° + 18° + x = 180°


⇒ x = 90°


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