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Official SolutionGiven: • Triangle ABC is inscribed in a circle.
• One of the sides of triangle ABC is the diameter.
• O is the centre and the radius is 6 units.
• angle ABC>angle BAC>angle ACB.
• angle OAB = \(60^o\)
Working:ABC is inscribed in a circle, with one of the sides as the diameter.
Thus, we can conclude that
ABC must be a right-angled triangle since we know that
the diameter subtends an angle of 90 degrees on the circumference.Also, angle ABC>angle BAC>angle ACB,
Therefore,
we can infer angle ABC = \(90^o\) and AC is the diameter of the circle.
From the above diagram,
We can infer that
OBA an equilateral triangle and OBC is an isosceles triangle. Hence,
OB = OA = AB = 6 units.As triangle ABC is a right-angled triangle,
We can apply Pythagoras Theorem and write:
A\(B^2\) + B\(C^2\) = A\(C^2\)
\(6^2\) + B\(C^2\) = 1\(2^2\)
B\(C^2\) = 1\(2^2\) - \(6^2\)
BC = \(6\sqrt{3}\)
Hence,
correct option is BThanks,
Saquib
Quant Expert
e-GMAT