Triangles and Quadrilaterals

There are certain triangles and quadrilaterals that occur often enough to be given special names. Sometimes I get some of the terminology confused, so I thought I could dedicate one of my posts to explaining what each of them mean.

Let's first start with triangles (three-sided polygons). An acute triangle is when all three angles within the triangle are acute (less than 90 degrees, but more than 0). A right triangle contains one right angle (90 degrees). An equilateral triangle is a triangle that has all three sides of equal length. A scalene triangle is a triangle that has three sides of different length. An isosceles triangle has at least two sides of equal length. Lastly, an obtuse triangle has one angle that is obtuse (greater than 90 degrees, but less than 180 degrees).

Now, I am going to go over quadrilaterals (four-sided polygons). A trapezoid has exactly one pair of opposite sides that are parallel. An isosceles trapezoid is a trapezoid in which its non-parallel sides are congruent. A rhombus has opposite sides that are parallel and all sides have equal length. A parallelogram has pairs of opposite sides that are parallel and of equal length. A rectangle has pairs of opposite sides that are parallel and of equal length, and contains all right angles. Lastly, a square has all sides of equal length and contains all right angles.

Hopefully, this helped a little bit with trying to figure out what makes each of them different from each other. I also found a game that relates to triangles and quadrilaterals.