Question

in the given figure O is the centre of the circle and ABCD are equal charts

Answer 1

Heya

Equal chords subtend equal angles at the centre.

Angle subtended by AB at the centre will be equal to the angle subtended by CD at the centre.

So we get, angle COD = 70°

In ∆COD, OC=OD

They are the radii of the circle.

So, ∆COD is isosceles triangle.

In an isosceles triangle angles opposite to equal sides are equal.

Angle OCD = angle ODC = y

70+y+y=180° [Angle sum property of traingle]

70+2y=180

2y=180-70

y=110/2

y=55°

Angle OCD = 55°