Geometry!
100
A 10 sided figure! :D
What is a decagon! (Good job! if you got it right!)
200
a parallelagram with 4 right angles and 4 congruent sides...
What is a square? Hopefully you got that right.... if you didn't go back to kindergarden! ;D
300
A triangle with no congruent sides
What is an isosceles triangle (OHH YEAA!!! :D)
400
Two angles whose measures add up to 90 degrees!
What is complementary! BOOM! :)
500
A parallelogram with 4 congruent sides...
What is a rhombus! :D