[color=#000000]Use coordinate geometry to prove that [/color][b][color=#1e84cc]both diagonals of an isosceles trapezoid[/color] [/b][color=#000000]are[/color][b] [color=#1e84cc]congruent.[br][/color][/b][color=#000000]That is, write a coordinate geometry proof that formally proves what this applet informally illustrates. [br][br]Be sure to assign appropriate variable coordinates to your isosceles trapezoid's vertices! [br](The maximum number of variable coordinates your coordinate setup should have is 3.) [/color]

[color=#000000]Now prove this same theorem true using the format of a 2-column proof or a paragraph proof.[br][i]Hint: This proof will contain at least one pair of congruent triangles. [/i][/color]