The video tutorial explains how to find the equation of a line perpendicular to a given line N that passes through a specific point. It covers the concept of gradients, particularly how to calculate the gradient of line N using a right-angled triangle. The tutorial then explains how to find the gradient of a perpendicular line by taking the reciprocal and changing the sign. Finally, it derives the equation of the new line using the y-intercept and discusses the marking scheme for the problem.

What is the y-intercept (c) of the new line that is perpendicular to line N?

Explain the process of finding the reciprocal of a gradient and changing its sign.