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Shapes Comparison (Sides & Angles):

QUADRILATERIALS - 4 SIDES & 4 ANGLES 5

QUADRILATERIAL - ANY 2D shape with FOUR (4) SIDES and FOUR (4) ANGLES and can be classified into the following five regular shapes:

  1. Trapezoid
  2. Kite
  3. Square
  4. Rectangle
  5. Rhombus

The last three quadrilaterals (Square, Rectangle, and Rhombus) are referred to as parallelograms.

PARALLELOGRAM - ANY quadrilateral that has TWO (2) PAIRS of PARALLEL SIDES that are OPPOSITE AND EQUAL in length. Opposite angles are equal but not necessarily right angles.

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Lines are said to be
PARALLEL if they
are always the same
distance apart and
point in the same
direction so that they
will never meet.


TRIANGLES - 3 SIDES & 3 ANGLES 3

TRIANGLE - ANY 2D shape with THREE (3) SIDES and THREE (3) ANGLES and can be classified into the following three regular shapes:

  1. Right Triangle
  2. Acute Triangle
  3. Obtuse Triangle

CIRCLE - 0 (STRAIGHT) SIDE & 0 ANGLE 1

CIRCLE - a 2D shape that has NO STRAIGHT SIDES AND NO ANGLES. Unlike the other types of 2D shapes (quadrilateral or triangle), there is only ONE type of circle.

OPTIONAL: INTERESTING FACTS and MEMORIZATION TIP

INTERESTING FACTS:

  • There are three shapes that have ALL equal parts:
  • A SQUARE has ALL equal sides and ALL equal right angles (90°).
  • An ISOSCELES TRIANGLE has ALL equal sides and ALL equal angles (60°).
  • A CIRCLE has ALL equal radii and ALL equal diameters.

MEMORIZATION TIP: Notice the pattern for each 2D SHAPE:

  • 4 x 4 - QUADRILATERAL - has 4 sides and 4 angles
  • 3 x 3 - TRIANGLE - has 3 sides and 3 angles
  • 0 x 0 - CIRCLE - has 0 side and 0 angle
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An ISOSCELES
TRIANGLE is a
2D shape with
AT LEAST TWO
EQUAL SIDES.

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An SQUARE is a 2D
shape with FOUR
EQUAL SIDES and
FOUR EQUAL ANGLES.

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A CIRCLE is a 2D shape with NO
STRAIGHT SIDES OR ANGLES.
A drawing showing a circle with the diameter and radius measurements inside of the circle.