In the given circle, chord \(\overline {AB}\) is extended to meet the tangent \(\overline {DE}\) at D. If \(\overline {AB}\) = 10 cm and \(\overline {DE}\) 12 cm, what is the length of B̅D̅?
In the given circle, chord \(\overline {AB}\) is extended to meet the tangent \(\overline {DE}\) at D. If \(\overline {AB}\) = 10 cm and \(\overline {DE}\) 12 cm, what is the length of B̅D̅? Correct Answer 8 cm
⇒ Let BD = x
⇒ Formula, DE2 = DB × DA
122 = x(x + 10)
⇒ 144 = x2 + 10x
⇒ 0 = x2 + 10x - 144
⇒ 0 = x2 + 18x - 8x - 144
⇒ 0 = x(x + 18) - 8(x + 18)
⇒ 0 = (x + 18) (x - 8)
⇒ x = -18 (Not possible)
x = 8 cm
মোঃ আরিফুল ইসলাম
Feb 20, 2025