Q1 of 29 Page 63

O is the centre of the circle. AB is the chord and D is mid-point of AB. If the length of CD is 2cm and the length of chord is12 cm, what is the radius of the circle

In triangle AOD


AD = 6cm


AO = r


OD = OC–CD = r–2


Applying Pythagoras theorem we get





r = 10cm

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In the figure at right, ABCD is a cyclic quadrilateral in which ∠BCD = 100°and ∠ABD = 50°. Find ∠ADB

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In the figure at left, O is the centre of the circle, ∠AOC = 100° and side AB is produced to D.

Find (i) ∠CBD (ii) ∠ABC


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ABCD is a cyclic quadrilateral. Given that ∠ADB + ∠DAB = 120°and ∠ABC + ∠BDA = 145°. Find the value of ∠CDB

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In the given figure, AB is one of the diameters of the circle and OC is perpendicular to it through the center O. If AC is 7√2 cm, then what is the area of the circle in cm2