in a triangle ABC, AB=AC=15cm, BC=18cm find cos angle ABC.
Answers
Answered by
1
AB = a = 15
BC = b = 18
AC = c = 15
a² = b² + c² - 2bc cosA
AB² = BC² + AC² - 2(BC)(AC) cos(ABC)
15² = 18² + 15² - 2*18*15* cos(ABC)
cos(ABC) = 18² / (2*18*15) = 3/5 = 0.6
BC = b = 18
AC = c = 15
a² = b² + c² - 2bc cosA
AB² = BC² + AC² - 2(BC)(AC) cos(ABC)
15² = 18² + 15² - 2*18*15* cos(ABC)
cos(ABC) = 18² / (2*18*15) = 3/5 = 0.6
Similar questions
BC = b = 18
AC = c = 15
a² = b² + c² - 2bc cosA
AB² = BC² + AC² - 2(BC)(AC) cos(ABC)
15² = 18² + 15² - 2*18*15* cos(ABC)
cos(ABC) = 18² / (2*18*15) = 3/5 = 0.6