Hey!
The average height of 5 people is 5.9.
The total height is equal to:
[tex] 5.9 \times 5 = 29.5 [/tex]
4 people are each 5.8. Their total height is equal to:
[tex] 5.8 \times 4 = 23.2 [/tex]
Subtract the total height of 4 people with the total height of all 5 players:
[tex] 29.5 - 23.2 = 6.3 [/tex]
[tex] \framebox{The height of the 5th player is 6.3} [/tex]