{ Word List: tri-
to cut into three parts
trisect
three related plays or novels
trilogy
a race that combines three activities—swimming, bicycling and running
triathlon
a vehicle with three wheels
tricycle
able to speak three different languages
trilingual
having or involving three sides, countries, or parties
trilateral
a three- legged stool, table or stand to hold things, such as a camera
tripod
a group of three people or things
trio
a dinosaur with three horns—two long horns above the eyes and one short horn on the nose
triceratops
a three-sided figure
triangle
sect = cut lateral = side
Perimeter means adding all the sides together.
Triangles can be equilateral which means all sides are equal.