A Right Isosceles on an Ellipse

The ellipse $C:\dfrac{x^2}{25}+\dfrac{y^2}{m^2}=1$ ($0<m<5$) has eccentricity $\dfrac{\sqrt{15}}4$. Let $A$ and $B$ be the left and right vertices of $C$.

1. Find the equation of $C$. 2. A point $P$ lies on $C$ and a point $Q$ lies on the line $x=6$, with $|BP|=|BQ|$ and $BP\perp BQ$. Find the area of $\triangle APQ$.