Question

In the given figure BD=AD=DC and angle ABE=125degree, the value of angle ACB is

Answer 1

Answer:

in triangle ABC,

AB=AC implies that ABC is an isoceles triangle

let one of its equal angle be x then ,

x +x+∠A = 180°  ( ANGLE SUM PROPERTY )

⇒ 2x + ∠A = 180° ...... EQ.1

ALSO ,∠A+x = 125°    (EXTERIOR ANGLE PROPERTY )

MULTIPLYING THE ABOVE EQUATION BY 2 WE GET ,

2∠A+2x = 250° ......... EQ. 2

SUBTRACTING EQ. 1 FROM EQ.2 ,

2∠A + 2x -2x -∠A= 250°-180°

⇒∠A = 70°

HOPE IT HELPED