Ques 15 (b) In the figure (i) given below, AC is a diameter of the given circle and ∠BCD = 75°. Calculate the size of (i) ∠ABC (ii) ∠EAF.

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deepaksoniGuru

Asked: March 31, 20212021-03-31T08:14:03+05:30 2021-03-31T08:14:03+05:30In: ICSE

This is the basic and conceptual question from Chapter name- circles
Topic – Angle properties of circles
Chapter number- 15

In this ques , AC is a diameter of the given circle and ∠BCD = 75°. And we have to Calculate the size of (i) ∠ABC (ii) ∠EAF.

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Understanding ICSE Mathematics
Question 2(b)

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AAREKH · Answer 1 · 2021-04-01T06:38:15+05:30

AAREKH Guru

(b) (i) AC is the diameter of the circle

∠ABC = 90^o(Angle in a semi-circle)

(ii) ABCD is a cyclic quadrilateral

∠BAD + ∠BCD = 180^o

∠BAD + 75^o= 180^o

(∠BCD = 75^o)

∠BAD = 180^o-75^o = 105^o

But ∠EAF = ∠BAD

(Vertically opposite angles)

∠EAF = 105^o