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## Geometric Plane Shapes: Circles, Triangles, Rectangles, Squares, and Trapezoids

What are geometric plane shapes? What characteristics do they have? These are the questions that we will answer in this post.

The principal geometric plane shapes are:

#### The Circle The circle is a shape that can be made by tracing a curve that is always the same distance from a point that we call the center. The distance around a circle is called the circumference of the circle.

#### The Triangle The triangle is a shape that is formed by 3 straight lines that are called sides. There are different ways of classifying triangles, according to their sides or angles.

1. According to their angles:
• Right triangle: the largest of the 3 angles is a right angle.
• Acute Triangle: the largest of the 3 angles is an acute angle (less than 90 degrees).
• Obtuse Triangle: the largest of the 3 angles is an obtuse angle (more than 90 degrees).

2. According to their sides:

• Equilateral Triangle: all 3 sides are the same length.
• Isosceles Triangle: it has 2 (or more) sides that are of equal length. (An equilateral triangle is also isosceles.)
• Scalene Triangle: no 2 sides are of equal measure.

#### The Rectangle The rectangle is a shape that has 4 sides. The distinguishing characteristic of a rectangle is that all 4 angles measure 90 degrees.

#### The Rhombus The rhombus is a shape formed by 4 straight lines. Its 4 sides measure the same length but, unlike the rectangle, any of all 4 angles measure 90 degrees.

#### The Square The square is a type of rectangle, but also a type of rhombus. It has characteristics of both of these. That is to say, all 4 angles are right angles, and all 4 sides are equal in length.

#### The Trapezoid The trapezoid also has 4 sides. It has two sides that are parallel but the other 2 are not.

You can practice with the geometric plane shapes by registering in Smartick.