The points A,B and C have position vectors given respectively
a = ( 7i + 4j -2k) b= ( 5i + 3j - 3k) c= ( 6i + 5j - 4k)
a) Find the angle BAC
b) Find the area of the triangle ABC
i have dont part a) and got 60 degrees but i cant do part b)
thanks in advance!