Wednesday 8 January 2014

CIRCLES B2

Find x on the following figure





solution



According to rectangle properties of a circle

(CX)(XD) = (AX)(XB)

(x)(x + 3) = (5)(2)

x2 + 3x = 10

x2 + 3x – 10 = 0 [ solving by factorization ]

x2 + 5x – 2x – 10 = 0 [ splitting 3x into 5x and (-2x) ]

x(x + 5) – 2(x + 5) = 0

 (x + 5) (x - 2) = 0

x + 5 = 0 or x - 2 = 0

x = -5 or x = 2

Since there is no negative length, we take x=2cm.

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