An ellipse has a center at the origin, a vertex along the major axis at open paren 20 comma 0 close paren , and a focus at open paren 16 comma 0 close paren The equation of the ellipse is in the form. the fraction with numerator x squared and denominator A squared plus the fraction with numerator y squared and denominator b squared is equal to 1 What is the value of b in the equation?
The vertex at (20, 0) means the semi-major axis is a = 20, and the focus at (16, 0) means c = 16. For an ellipse, a² = b² + c², so b² = 20² − 16² = 400 − 256 = 144. Therefore b = 12, which is choice B.
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