If the length of the major axis of the ellipse (x2)/(a2) +...

We have

$\dfrac{x2}{a2} + \dfrac{y2}{b2} = 1$

Given,

$\text{Length of the major axis} = 3 \left(\text{Length of the minor axis}\right)$

$⇒ \left(2a\right) = 3 \left(2b\right)$

$⇒ a = 3b$

Now,

$e = \sqrt{1 - \dfrac{b2}{a2}}</p><p>$⇒ e = $\sqrt{1 - \dfrac{b2}{9b^{2}}}</p><p>$⇒ e = $\sqrt{1 - \dfrac{1}{9}} =\dfrac{8}{3} =\dfrac{2\sqrt{2}}{3}$