An ellipse centered at the origin has vertices at (13, 0) and (-13, 0) and foci at (12, 0) and (-12, 0). What is b squared?

1. The vertices are at plus and minus 13 on the x-axis, so a is 13 and a squared is 169. 2. The foci are at plus and minus 12 on the x-axis, so c is 12 and c squared is 144. 3. For an ellipse the three are tied by c squared equals a squared minus b squared. 4. Substituting gives 144 equals 169 minus b squared, so b squared is 25. 5. Answering 5 stops at b itself rather than the b squared the question asks for. _Source: OpenStax College Algebra (CC BY 4.0), Ch 8 "Analytic Geometry", section 8.1 The Ellipse_