It is known that P is the point on the ellipse x ^ 2 / 49 + y ^ 2 / 24 = 1, and F1 and F2 are the focal points. If Pf1 is perpendicular to PF2, then the area of triangle pf1f2 is A.28 B.24 C.22 D.20

Let point P coordinate be (x1, Y1), x ^ 2 / 49 + y ^ 2 / 24 = 1, a = 7, B = √ 24 = 2 √ 6, C = √ (a ^ 2-B ^ 2) = 5, where X1 ^ 2 / 49 + Y1 ^ 2 / 24 = 1, 24x ^ 2 + 49y1 ^ 2 = 49 * 24. Let the slope of line Pf1 be kpf1, and the slope of line PF2 be kpf2

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