Answer :
(If i made a mistake, please let me now)
b² = c² - a²
b² = (18.5)² - (6)²
b² = (342.25) - (36)
b² = √306.25 = 17.5
17.5 = 18
b² = c² - a²
b² = (18.5)² - (6)²
b² = (342.25) - (36)
b² = √306.25 = 17.5
17.5 = 18