Grade 3 Geometry: Quadrilaterals

Worked examples

Real problems from the practice worksheets, solved one step at a time.

1. Example 1

   I have 3 sides and 3 corners, so I am NOT a quadrilateral. What shape am I?

   1. The shape has 3 sides and 3 corners — a quadrilateral has 4, so it is not one.
   2. A polygon with 3 sides is a triangle.
   3. So the shape is a triangle.

   Answer: triangle

2. Example 2

   Maya draws 5 quadrilaterals. How many sides did she draw in all?

   1. Every quadrilateral has 4 sides.
   2. 5 quadrilaterals have 5 × 4 = 20 sides.

   Answer: 20

3. Example 3

   I have 4 right angles, but my sides are not all the same length. What is my most specific name?

   1. It has 4 right angles (square corners), so it is a rectangle.
   2. Its sides are not all the same length (2 are long and 2 are short), so it is not a square.
   3. Its most specific name is rectangle.

   Answer: rectangle