Question

plz anybody solve question no. 3.the answer is 60.class 9

Answer 1

In Triangle BDC, BD = CD

                Hence, ∠B = ∠C

             so, ∠B = ∠C = 30°

Hence, ∠D = 180 - 60 = 120 ° [Using Angle Sum Property]

Now, ∠D + ∠BAC = 180° [Sum of Opp. ∠s of cyclic Quadrilateral is 180°]

Hence, ∠ BAC = 180 - 120

           ∠ BAC = 60°

Answer 2

Answer:

Step-by-step explanation:

Since BD = DC, triangle BDC is an isosceles triangle,

=> DCB = 30 degree

in triangle BDC,

30 + 30 + BDC = 180

BDC = 120

ABCD is a cyclic quadrilateral,

=> D + A = 180         [Sum of opposite angles in cyclic quadrilateral is 180]

=> 120 + A = 180

=> A = 60