A square has four right angles (90°). Each diagonal splits a corner into two angles of 45°. Note also that the diagonals cut each other in half at right angles. A rectangle has four right angles. The ...

The base and perpendicular height are at right angles. Showing that a parallelogram has the same area as a rectangle: Split the parallelogram into a right-angled triangle and a trapezium. Move the ...

Proving that two polygons have the same area can be as easy as cutting them up and rearranging the pieces. Gina the geometry student stayed up too late last night doing her homework while watching The ...

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. What is a quadrilateral? A quadrilateral is a four-sided shape where each of the sides are straight and ...