L1 [x,y]=[2,1]+r[-5,1]
L2 [x,y]=[1,4]+s[2,1]
L3 [x,y]=[3,5]+t[4,-5]
These three lines are sides of a triangle
find: 1)the perimeter of the triangle
2) The largest angle
3) the centroid of the triangle
so I converted the vector equations into parametric, and then made two of the x parametric...