The sum of the focal distances of any point on the ellipse 9x2 + 16y2 = 144 is
Given ellipse is 9x2 + 16y2 = 144. It is rewritten as
⇒ 
⇒ 
Comparing with standard equation 
we get
⇒ a2 = 16
⇒ a = 4
We know that the sum of the focal distances of any point on the ellipse is 2a.
⇒ 2(4) = 8
∴ The correct option is D
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