[color=#000000]Use coordinate geometry to prove that the [b]diagonals of a rhombus are perpendicular. [/b] [br][br][/color][color=#000000]That is, write a coordinate geometry proof that formally proves what this applet informally illustrates. [br]Be sure to assign appropriate variable coordinates to your rhombus's vertices! [br][br](Believe it or not, the maximum number of variable coordinates you'll actually need is 2.) [br](You can use 3 variable coordinates if you're willing to work with a system of equations.) [/color]

[color=#000000]Now prove this same theorem true using the format of a 2-column proof or a paragraph proof.[/color]