Q3 of 15 Page 87

The bottom side of the quadrilateral in the picture is a diameter of the circle and the top side is a chord parallel to it. Calculate the area of the quadrilateral.


O is the centre of the circle.


CD is the diameter, CD = 5 cm


EF is the chord parallel to CD, EF = 3 cm


OG is perpendicular drawn on EF from O.


In ΔOGE we have,


∠OGE = 90° [∵ OG is perpendicular on EF]


OE = 5/2 = 2.5 cm [∵ Diameter = 5 cm]


EG = 3/2 = 1.5 cm [∵perpendicular drawn from centre bisects chord]



∴ Area of the quadrilateral,




= 8 cm2


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