Question

If a line intersects two concentric circles with centre '0' at A, B,C and D, prove that AB=CD

Answer 1

What is concentric circle

Answer 2

we have

AD as a chord and also BC as a chord

we have OM perpendicular to this chords

As OM is perpendicular to BC

therefore; BM=CM ____________(1)

we also have OM perpendicular to AD

therefore; AM=DM ____________(2)

Subrating equation(1) from equation(2) we get

AM-BM =DM-CM

AB=CD

Hence proved