After Zeph had stacked up 15 chairs in the school field after a parade, he noticed 3 things. Firstly, each of the chairs was stacked the same height above the other. Secondly, the foot of the ninth chair was 85.6 cm above that of the first. Thirdly, the chairs reached a height of 236 cm. What is the height of each chair?
Number of chairs that contributed to the height of 85.6 cm above the first chair
= 9 - 1
= 8

Height increase with each additional stacked chair
= 85.6 ÷ 8
= 10.7 cm

Number of chairs stacked on top of the first chair
= 15 - 1
= 14

Height increase of 14 additional stacked chairs
= 14 x 10.7
= 149.8 cm

Height of one chair
= 236 - 149.8
= 86.2 cm

Answer(s): 86.2 cm