Grade Level: 3rd Skill: Shapes and Geometry Topic: Rectangles and Other Quadrilaterals Goal: Identify attributes of quadrilaterals (e.g., parallel sides for the parallelogram, right angles for the rectangle, equal sides and right angles for the square). Skill Description: Measurement and Geometry: attributes of quadrilaterals The ability to identify a figure as a quadrilateral based on its attributes and the ability to classify the quadrilateral as a specific type of quadrilateral.

### Sample Problems

 (1) What is a quadrilateral? A quadrilateral is a polygon that has exactly four sides. (2) There are different types of quadrilaterals: Trapezoids have one pair of opposite sides parallel. Isosceles trapezoids have congruent base angles (base angles are the two angles at either end of one of the parallel sides). A parallelogram has two pairs of opposite sides parallel. A rhombus has all four sides the same length. A square is a rhombus with only right angles. A rectangle only has right angles. (3) What quadrilateral has for equal sides and four right angles? (square) (4) What quadrilateral has one pair of opposite sides that are parallel? (trapezoid) (5) What is a rhombus? A shape that has all four sides the same length, like a square.

### Learning Tips

 (1) A quadrilateral is a four-sided polygon with four angles. The most common quadrilaterals are parallelogram, rectangle, square, rhombus and trapezoid. (2) A parallelogram has opposite sides parallel and congruent. A rectangle has four right angles and because it has two pairs of parallel sides it is also a parallelogram. A square has four right angles and four congruent sides. It is also a rectangle and a parallelogram. A rhombus is a parallelogram with four equal sides. A rhombus is not always a rectangle because it may not have 4 right angles. A trapezoid has only one pair of parallel lines. It’s a quadrilateral that is not a parallelogram. (3) All quadrilaterals have two diagonals and the sum of their four interior angles is 360 degrees. (4) Explain the term congruent. Congruent means that they (i.e. shapes, sides) are identical in shape and size. (5) Define parallel lines. Parallel lines are always the same distance apart and will never meet.

### Online Resources

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