The general notation in geometry is that points are labeled with capital letters and coordinates are defined with lowercase letters.

Question

Given the two points A(x₁, y₁) and B(x₂, y₂) what do the subscripts on x and y represent? If triangle ABC is a right triangle with C being the right angle, find expressions for the lengths of all three sides.

Answer 1

subscripts allow you to identify different points; point A has both x and y coordinates, as does point B, so these are distinguished by x sub one and x sub two, for points A and B, respectively.

 

For the second question, draw the right triangle ABC and label each side a, b, c, opposite the corresponding angles identified by their capitalized letters.  Of course, things such as a² + b² = c² and various trig functions apply.