Pitagora
AB = √AD² + BD² = √144 + 81 = √225 = 15 cm
Teorema catetei
AB² = BD·BC => BC = AB²/BD = 225/9 = 25 cm
Pitagora
AC = √BC² - AB² = √625 - 225 = √400 = 20 cm
sinB = AC/BC = 20/25 = 4/5
cosB = AB/BC = 15/25 = 3/5
tgC = AB/AC = 15/20 = 3/4
ctgC = AC/AB = 20/15 = 4/3