Polygons

I am 3 sides more than a pentagon. What am I?

An Octagon

I am a triangle with all three sides of equal length

Equilateral Triangle

I am 3 sides less than a decagon. What am I?

A Heptagon

I am a triangle with all three sides of unequal length.

Scalene Triangle

I am a triangle with only two sides of equal length.

Isosceles Triangle

I am double the sides as a hexagon. What am I?

A Dodecagon

I am a triangle with one right angle.

Right Triangle

I am a four-sided polygon with two pairs of parallel sides.

Parallelogram

I am 1 side more than a decagon. What am I?

An undecagon

I am a four-sided polygon having equal sides meeting at right angles.

Square

I am a four-sided polygon having all four sides of equal length.

Rhombus

I am 2 lines that never touch. What am I?

Parallel Lines

I am a four-sided polygon having exactly one pair of parallel sides. This Photo by Unknown Author is licensed under CC BY-SA

Trapezoid

I am a four-sided polygon having all right angles (opposite sides are equal)…

Rectangle

I am a five-sided polygon.

Pentagon

I have seven-sided polygon.

Heptagon

I am a six-sided polygon.

Hexagon

I am 4 sides more than a pentagon. What am I?

A nonagon

I am an eight-sided polygon.

Octagon

I am a ten-sided polygon. What am I?

Decagon

I am a nine-sided polygon. What am I?

Nonagon

I have half the sides as a decagon. What am I?

A pentagon

I am an eleven-sided polygon.

Undecagon

I am 2 lines that touch. What am I?

Perpendicular Lines

I am a twelve-sided polygon. What am I?

Dodecagon