Foci of an ellipse

Question

How far apart are the foci of an ellipse with a major axis of 32 cm. and a minor axis of 14 cm.?

Answer 1

Length of the major axis 2a =32 cm

                                    a = 16 cm   

Length of the minor axis 2b =14 cm

                                    b =7 cm

Calculate the value of C:

C = √(a²-b²)

    = √(16²-7²)

    = √207

    =√9*23

      =3√23

Distance between foci is  2C =6√23