Question

the length of the major axis of the ellipse below is 13 what is the sun of the lengths of the red and blue line segments

Answer 1

The distances a, b, and c, in an ellipse, are related like this

$a^2=b^2+c^2$

Where 2c is 13, according to the problem.

Let's find c

$\begin{gathered} 2c=13 \\ c=\frac{13}{2}=6.5 \end{gathered}$

The blue line is equal to a, and the sum of the red and blue lines is 2a.