Hello,

the foci have the distance e (called linear eccentricity (literally translated from German)) from the centre of the ellipse. The proportion is called numerical eccentricity (translated ... as you now know) and that's the value you are given here.

Thus you can calculate the distance e:

If you subtract this value from the half axis you'll get the shortest distance (it is called perihel) p = 91,446,900 miles

If you add this value to the half axis you'll get the greatest distance (it is called aphel) ap = 94,553,100 miles

EB

PS: Make a sketch of an ellipse and mark the lines a, b, e, p and ap.