Is .63 the eccentricity of the ellipse x^2/49 + y^2/81 =1

Question

anonymous · Answer

yes

anonymous · Answer

to two decimal places

anonymous · Answer

Thank  you. I'm having a hard time figuring this out. I know the formula is e = c^2/a but I don't get this answer. I'm guessing. Any suggestions?

anonymous · Answer

$$\sqrt{1-(\frac{9}{7})^2}$$

anonymous · Answer

or 
$$\sqrt{\frac{a^2-b^2}{a^2}}$$

anonymous · Answer

by which i mean 
$$\sqrt{\frac{a^2-b^2}{a^2}}=\sqrt{1-(\frac{b}{a})^2}$$ so you can use whatever you find easiest

anonymous · Answer

sorry i had your backwards. it should have been $$\sqrt{1-(\frac{7}{9})^2}$$

anonymous · Answer

the thing inside the radical must be positive, so the bigger number goes irst or in the denominator

anonymous · Answer

My lesson says the formulat is y = a^2/c so I get 81/4 = 20.25. Where am I going wrong?