Question

Let the co-ordinates of one vertex of $\Delta ABC$ be $A(0, 2, \alpha)$ and the other two vertices lie on the line $x+\frac{\alpha}{5}=y-\frac{1}{2}=z+\frac{4}{3}$ For $\alpha∈Z$, if the area of $\Delta ABC$ is 21 sq. units and the line segment BC has length $2\sqrt{21}$ units, then α2 is equal to ___________.

Answer 1

The correct answer is 9