Q12 of 100 Page 17

In Fig. 16.184, if ∠BAC=60° and ∠BCA=20°, find ∠ADC.

By using angle sum property in triangle ABC,

∠B = 180^o – (60^o + 20^o)

= 100^o

In cyclic quadrilateral ABCD, we have

∠B + ∠D = 180^o

∠D = 180^o – 100^o

= 100^o

In a cyclic quadrilateral ABCD, if m ∠A =3(m∠C). Find m∠A.

In Fig. 16.183, O is the centre of the circle ∠DAB=50°. Calculate the values of x and y.

In Fig. 16.185, if ABC is an equilateral triangle. Find ∠BDC and ∠BEC

In Fig. 16.186, O is the centre of the circle. If ∠CEA=30°, find the values of x, y and z.