12 terms

Acute Triangle

a triangle with 3 acute angles

Obtuse Triangle

a triangle with one obtuse angle

Right Triangle

a triangle with 1 right angle

Equilateral Triangle

a triangle with three equal sides

Isosceles Triangle

a triangle with two congruent sides

Scalene Triangle

a triangle with no congruent sides

Quadrilateral

a polygon with 4 sides

Parallelogram

A quadrilateral with two pairs of parallel sides

Trapezoid

a quadrilateral with exactly one pair of parallel sides

Rhombus

a parallelogram with 4 congruent sides

Rectangle

a parallelogram with four right angles

Square

having four equal sides and four right angles or forming a right angle