Question

AB is the diameter of a circle with Centre O and CD parallel to AB. If angle bac =20°, then find the measure of the angle CoD

Answer 1

Answer:

40°

Step-by-step explanation:

theorem : Angles opposite to equal sides of a triangle are equal.

in ∆ OAC,

OA = OC = radius

hence

^OAC = ^OCA = 20° ( above theorem)

then...

^AOC = 180° - (20°+20°) = 140°

but...

^ COD = 180° - ^AOC = 40°