[tex]\bold{\text{Answer: b.}\quad \dfrac{y^2}{100}+\dfrac{x^2}{49}=1}[/tex]
Step-by-step explanation:
The ellipse is vertical so y has the biggest radius.
Major axis (y) = 20 so the y-radius is 20/2 = 10
Minor axis (x) = 14 so the x-radius is 14/2 = 7
The equation of an ellipse is: [tex]\dfrac{(x-h)^2}{a^2}+\dfrac{(y-k)^2}{b^2}=1[/tex] where
- (h, k) is the center of the ellipse
- a is the x-radius
- b is the y-radius
Given: a = 7, b = 10
Assume: (h, k) = (0, 0)
[tex]\dfrac{(x-0)^2}{7^2}+\dfrac{(y-0)^2}{10^2}=1\\\\\\\dfrac{x^2}{49}+\dfrac{y^2}{100}=1\\\\\\\longrightarrow \dfrac{y^2}{100}+\dfrac{x^2}{49}=1[/tex]
