After Zane had stacked up 10 chairs in the parade square after a gathering, he noticed 3 things. Firstly, each of the chairs was stacked the same height above the other. Secondly, the foot of the fourth chair was 26.4 cm above that of the first. Thirdly, the chairs reached a height of 172.8 cm. What is the height of each chair?
Number of chairs that contributed to the height of 26.4 cm above the first chair
= 4 - 1
= 3

Height increase with each additional stacked chair
= 26.4 ÷ 3
= 8.8 cm

Number of chairs stacked on top of the first chair
= 10 - 1
= 9

Height increase of 9 additional stacked chairs
= 9 x 8.8
= 79.2 cm

Height of one chair
= 172.8 - 79.2
= 93.6 cm

Answer(s): 93.6 cm