Chords AB and CD of a circle, when produced, meet at the point P. If AB = 6.3 cm, BP = 4.5 cm, and XD = 3.6, then the length (in cm) of PD is
Answer & explanation
Correct answer: option 4
AB = 6.3 cm,
BP = 4.5 cm,
and CD = 3.6 cm
Let, PD = a cm
We know,
PB × PA = PD × PC
= PB × (PB + BA) = PD × (PD + DC)
= 4.5 × (4.5 + 6.3) = a × (a + 3.6)
= 4.5 × 10.8 = x2 + 3.6x
= 48.6 = a2 + 3.6a
= 10a2 + 36a - 486 = 0
= 5a2 + 18a - 243 = 0
So, by solving further ,
here a = 5.4