MG 2.3
Identify attributes of quadrilaterals (e.g., parallel sides for the
parallelogram, right angles for the rectangle, equal sides and
right angles for the square).
UNDERLYING SKILLS AND CONCEPTS:
visualize 2-dimensional figures;
classify 2-dimensional figures;
vocabulary for geometry
Identify Attributes of Quadrilaterals
parallelogram
rectangle
two pairs of sides of equal length
and two pairs of parallel sides
two pairs of sides of equal length
and four right angles
square
four sides of equal length
and four right angles
rhombus
trapezoid
four sides of equal length exactly two parallel sides
Sides of a quadrilateral can be parallel, perpendicular, or neither.
Sides that are parallel are the same distance apart at any point.
Sides that are perpendicular meet at a right angle.
Quadrilaterals can have one or more right angles (a quarter of a turn).
Quadrilaterals can have sides that are congruent (the same length).
E x am p l E
Describe the attributes of a rectangle.
How is a rectangle like a trapezoid?
Both figures have 4 sides.
Rectangle Trapezoid
So they are both quadrilaterals.
How is a rectangle different from a trapezoid?
Rectangle
Trapezoid
4 right angles
2 pairs of parallel sides
1 pair of parallel sides
2 pairs of congruent sides
1 pair of non–parallel sides
page 272
Chapter 23 – Lesson 4
C – © CSL Associates, Inc. All rights reserved.
a
K
ey Ide
Quadrilaterals are polygons with 4 sides and 4 angles.
Quadrilaterals have names that tell you about their sides and
angles.
Name
P RAC T I C E
Describe the sides and angles of each quadrilateral.
1.
opposite sides are parallel;
4 right angles; 2 pairs of congruent sides
2.
opposite sides are parallel;
no right angles; 2 sets of congruent sides
3.
opposite sides are parallel;
all sides are congruent; 4 right angles
4.
1 pair of opposite sides is parallel
C – © CSL Associates, Inc. All rights reserved.
no right angles; no congruent sides
5.
2 pairs of parallel sides; no right angles
all sides are congruent;
For each quadrilateral, draw an example that is different from those above.
6. rectangle
7. square
8. trapezoid
9. parallelogram
Math
Reasoning
Classify Quadrilaterals
MR 1.1
10. Is a square also a rectangle? Why or why not?
Yes; because the opposite sides of a square are parallel
and it has 4 right angles.
Chapter 23 – Lesson 4
page 273
MCX94.HW.CL.G3.FM&Lesson.v211
8/3/04
13:56
Page 184
Name
P RAC T I C E
…at home!
Describe the sides and angles of each quadrilateral.
1.
opposite sides are parallel;
no right angles; 2 pairs of congruent
sides (parallelogram)
opposite sides are parallel;
2.
4 right angles; 2 sets of congruent sides
(rectangle)
3.
opposite sides are parallel;
all sides are congruent; 4 right angles
(square)
1 pair of opposite sides is parallel
4.
(trapezoid)
2 pairs of parallel sides; no right angles
5.
2 pairs of congruent sides; (parallelogram);
For each quadrilateral, draw an example that is different from page 184.
6. parallelogram 7. trapezoid
8. square
9. rectangle
Math
Reasoning
Classify Quadrilaterals
MR 1.1
10. Is a rectangle also a square? Why or why not?
No; because a square has all sides congruent.
A rectangle may have two pairs of different length sides.
page 184
Home Resource and Homework
Chapter 23 Lesson 4
C – © CSL Associates, Inc. All rights reserved.
no right angles; no congruent sides
MCX94TEG3Ch01_32.v8.9.3 2/21/01 14:50 Page 503
Name
P RAC T I C E
Describe the sides and angles of each quadrilateral.
1.
opposite sides are parallel;
4 right angles; 2 pairs of congruent sides
2.
opposite sides are parallel;
no right angles; 2 sets of congruent sides
3.
opposite sides are parallel;
all sides are congruent; 4 right angles
4.
1 pair of opposite sides is parallel
C – © CSL Associates, Inc. All rights reserved.
no right angles; no congruent sides
5.
2 pairs of parallel sides; no right angles
all sides are congruent;
For each quadrilateral, draw an example that is different from those above.
6. rectangle
7. square
8. trapezoid
9. parallelogram
Math
Reasoning
Classify Quadrilaterals
MR 1.1
10. Is a square also a rectangle? Why or why not?
Yes; because the opposite sides of a square are parallel
and it has 4 right angles.
Chapter 23 – Lesson 4
Student Book Page
page 273
Name
P RAC T I C E
…at home!
Describe the sides and angles of each quadrilateral.
1.
opposite sides are parallel;
no right angles; 2 pairs of congruent
sides (parallelogram)
opposite sides are parallel;
2.
4 right angles; 2 sets of congruent sides
(rectangle)
3.
opposite sides are parallel;
all sides are congruent; 4 right angles
(square)
1 pair of opposite sides is parallel
4.
(trapezoid)
2 pairs of parallel sides; no right angles
5.
2 pairs of congruent sides; (parallelogram);
For each quadrilateral, draw an example that is different from page 184.
6. parallelogram 7. trapezoid
8. square
9. rectangle
Math
Reasoning
Classify Quadrilaterals
MR 1.1
10. Is a rectangle also a square? Why or why not?
No; because a square has all sides congruent.
A rectangle may have two pairs of different length sides.
page 184
Home Resource and Homework
Chapter 23 Lesson 4
C – © CSL Associates, Inc. All rights reserved.
no right angles; no congruent sides