# ABCD

Geometry Level 5

$$ABCD$$ is a quadrilateral inscribed in a circle with $$AB = 1$$, $$BC = 3$$, $$CD = 4$$ and $$DA = 6$$. What is the value of $$\sec^2 \angle BAD$$?

Details and assumptions

A quadrilateral is inscribed in a circle if all four of its vertices lie on the circle.

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