Boy = 1 unit, giraffe = 3 units. Together 4 units = 500 cm.

Boy1Giraffe111500 cm

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

  1. 4 units → 500 cm
  2. 1 unit → 500 ÷ 4 = 125 cm

The boy is 125 cm tall.

Check: giraffe 375 + boy 125 = 500 cm, and 375 = 3 × 125. ✓