Question:

A circle has the same centre as an ellipse & passes through the foci <span class="math-inline">F_1</span> & <span class="math-inline">F_2</span> of the ellipse, such that the two curves intersect in 4 points. Let 'P' be any one of their point of intersection. If the major axis of the ellipse is 17 & the area of the triangle <span class="math-inline">PF_1F_2</span> is 30, then the distance between the foci is: