how do you find the spot where two lines intersect
To find the intersection of two straight lines: 1  First we need the equations of the two lines. If you do not have the equations, see Equation of a line - slope/intercept form and Equation of a line - point/slope form (If one of the lines is vertical, see the section below).
Then, since at the point of intersection, the two equations will have the same values of x and y, we set the two equations equal to each other. This gives an equation that we can solve for x. We substitute that x value in one of the line equations (it doesn't matter which) and solve it for y.