Father is 9 equal units = 171 cm. May is 7⁄9 of her father, so 7 of those units.

Father191919191919191919May19191919191919171 cm

Plain numbers are given; italic underlined numbers are worked out.

  1. Father = 9 units → 171 cm
  2. 1 unit → 171 ÷ 9 = 19 cm
  3. May = 7 units → 7 × 19 = 133 cm

May’s height is 133 cm.

Check: 7⁄9 of 171 = 133 cm. ✓