Question

In the following figure, chord MN and chord RS intersect at point D. If RD = 15, DS = 4, MD = 8, find DN by completing the following activity:

Activity:

∴ MD × DN = `square` × DS   ...(Theorem of internal division of chords)

∴ `square` × DN = 15 × 4

∴ DN = `square/8`

∴ DN = `square`

Answer 1

∴ MD × DN = \[\boxed{\ce{RD}}\] × DS   ...(Theorem of internal division of chords)

∴ \[\boxed{8}\] × DN = 15 × 4

∴ DN = \[\frac{\boxed{60}}{8}\]

∴ DN = \[\boxed{7.5}\]