The cafe wall optical illusion posted on Twitter challenges people to figure out if the lines are straight or bend at an angle. A myriad of optical illusions keeps us glued to our screens as we keep ...

An angle is the space between two lines that start at the same point. This point is called the vertex. Angles measure the size of a turn in degrees. You can show degrees using the symbol ° after the ...

A full turn around a point equals 360º. If a full turn equals 360º, then the sum of the angles around a point must also be 360º. When you calculate angles around a point, you can use this fact to find ...

Horizontal lines run left to right, parallel to the horizon, with slope 0 and equation y = k. Vertical lines run top to bottom, perpendicular to the horizon, with undefined slope and equation x = k.