# It's all on the circle

Geometry Level 2

Given that $$a,b,c$$ and $$d$$ are 4 distinct non-zero real numbers such that the points $$\left(a,\dfrac{1}{a}\right)$$, $$\left(b,\dfrac{1}{b}\right)$$, $$\left(c,\dfrac{1}{c}\right)$$ and $$\left(d,\dfrac{1}{d}\right)$$ lie on a circle.

Find the value of $$a\times b\times c\times d$$.

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