Engineering Multivariable calculus 3rd tutorial problem

[mystic summit]

See if guys can tackle this problem:

“1. The three lines below define a triangle. Find its area.

x = −11 + 5s,
y = s,
z = −2 + 2s;

x = 1 + 2u,
y = 1 − u,
z = −2 − 4u;

x = −2 + 3t,
y = −1 + 2t,
z = −8 + 6t.

2. The vertices of the triangle in question 1 are three vertices of a parallelogram.What are the possi- bilities for the fourth vertex?

3. Find the centroid of the triangle in question 1. It is the point of intersection of the three medians of the triangle, or it is the point on one of the medians, two-thirds of the way from the vertex to the midpoint of the opposite side.”

[mystic summit]

Thats good, now how would i find the possibilities of the fourth vertex for question 2?….. each parallelogram is created by one of the sides…… it takes 2 sides of the triangle to form 1 parallelogram. And we have 3 sides in a triangle. maybe you would be able to form 2 parallelograms right? So i get 2 different vertices

Centroid… the centroid i just use a double integral to find the centroid?

If so what would the equation look like?