Question

4. If 2 i +37-6, 67-27+3k are two consecu tive sides of a triangle, then perimeter of triangle is​

Answer 1

Answer:

Given If vector 2i+3j-6k ,6i-2j+3k are two consecutive sides of a triangle then the perimeter of triangle is

Now we have

Vector PQ = 2 I + 3 j – 6 k

Vector QR = 6 I – 2 j + 3 k  

So PQ + QR = PR

So PR = (2 I + 3 j – 6 k) + (6 I – 2 j + 3 k)

         = 8 I + j – 3k

Now PQ = l PQ l = √2^2 + 3^2 + (- 6)^2  

                           = √49

                            = 7 units

Also l QR l = √6^2 + (- 2)^2 + 3^2

                  = √49

                  = 7 units

So PR = √8^2 + 1^2 + (- 3)^2

          = √74 units

Now perimeter = PQ + QR + PR

                           = √74 + 14 units