In Euclidean geometry, when they say a line intersects or bisects, do any of these terms means that it is at 90 degrees? Maybe when they say a line bisects, does it mean 90 degrees?
To get a familiar sense of 'angle', look beyond the plane and the sphere, i.e., what would be an 'angle' in 3D? On the cylinder and the cone?...Does VAT apply to these broader contexts?
Consider an equal-sided triangle connected to a square with side a. A straight line from
Q intersects the square at x and y. You have given x, find an equation for the intersection at y(x).
Find the reflection of the point A(3, 1) in the line L with equation r · (2i − j) = 0.
Use your answer to find the reflection in L of the line r · (i − j) − 2 = 0.