GEOMETRIC FIGURES

Concept: Geometry is the area of mathematics that deals with points, lines, angles, two-dimensional shapes, and three-dimensional figures. Here is a list of some common geometric figures, including triangles, parallelograms, trapezoids, and circles. “Congruent” means the same. “Parallel” means that 2 lines are equidistance apart, just like railroad tracks.

Triangles
A triangle has three sides and three angles. The sides of triangles can have different lengths and their angles can have different measures.
Equilateral triangle: | All sides and angles are congruent; each angle measures 60 degrees. |
Isosceles triangle: | Two sides and the two angles opposite these sides are congruent. |
Scalene triangle: | No sides and no angles are congruent. |
Right triangle: | One angle is a right angle (equal to 90 degrees). |
Acute triangle: | All three angles are acute (less than 90 degrees). |
Obtuse triangle: | One angle is obtuse (greater than 90 degrees). |

Parallelograms
Parallelograms: | The opposite sides of a parallelogram are parallel and congruent. The opposite angles are of equal measure. |
Rectangle: | special parallelogram with four right angles |
Rhombus: | special parallelogram with four sides of equal length |
Square: | special parallelogram/rhombus/rectangle with four sides of equal length and four right angles |

Trapezoid
Trapezoid | A trapezoid has only one pair of parallel sides (called bases). |

Circle
Circle | Most shapes have straight sides. A circle, on the other hand, has a curved edge. |