Question

ᴀɴꜱᴡᴇʀ ᴡɪᴛʜ ᴇxᴩʟᴀɴᴀᴛɪᴏɴ ɴᴇᴇᴅᴇᴅ .......

ᴡᴀʀɴɪɴɢ:-ꜱᴩᴀᴍᴍᴇʀꜱ ʙᴇ ᴀᴡᴀʀᴇ ᴏꜰ ᴍᴇ ​

Answer 1

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AB = AC = a

AD = b

AD perpendicular to BC (BC is tangent for smaller circle)

BD = DC (A perpendicular drawn from the centre of a circle to a chord, bisects the chord)

BC = BD + DC

BC = BD + BD

BC = 2BD

In ∆ADB,

by using pythegorus theorem

H² = B² + P²

AB² = BD² + AD²

a² = BD² + b²

BD² = a² - b²

$BD = \sqrt{a {}^{2} - b {}^{2} }$

BC = 2BD

BC = 2√a²- b²

$BC = 2 \sqrt{a {}^{2} - b {}^{2} }$

Answer : (d) 2 √a²-b²