Question

in the fig. BC is the diameter of the circle . If angle ACB = 30 then find angle ABC.​

Answer 1

Answer:

60° is your answer

Step-by-step explanation:

in ∆ABC

angle ACB = 30°

angle BAC = 90°. ( angle formed on the circumference of the circle through the diameter is equal to 90° )

therefore,

as,

sum of all angles of the triangle = 180°

angle ACB + angle BAC + angle ABC = 180°

30° + 90° + angle ABC = 180°

120° + angle ABC = 180°

angle ABC = 180° - 120°

angle ABC = 60°

thank u

Answer 2

angle ACB=1/2 angle AOB=30°

(angle subtended by chord or major are is half of that at the center)

angle AOB=60°

now AOB

AO=OB,angle OAB=angle OBA ( isosceles )

angle AOB+angle ABO+angleOAB=180°(sum of angle of a )

60°+2angleOAB=180°

2angle OAB=120°

angle OAB=60°