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 = x+ 18x - 8x - 144

⇒ 0 = x(x + 18) - 8(x + 18)

⇒ 0 = (x + 18) (x - 8)

⇒ x = -18 (Not possible)

x = 8 cm

Related Questions

Let the average temperatures in Centigrade (C) and Fahrenheit (F) be $$\overline C $$ and $$\overline F $$. If $$\overline C $$ and $$\overline F $$ are related to $$F = \frac{9}{2}C + 32,$$   then $$\overline F $$ and $$\overline C $$ have the relation