Areas of Rectangles
Lesson 11.1
Geometry Honors
Objectives:
1. Understand the areas postulate.
2. Know and use the formula for the area
of rectangle.
Lesson Focus
The concept of the area of a geometric figure is introduced in
this lesson. Three postulates are stated that give basic
information about the area of a square, areas of congruent
figures, and additional areas. The formula for the area of a
rectangle is proved as a theorem.
Areas of Rectangles
Postulate
The area of a square is the square to the length of a side.
A = s2
Areas of Rectangles
Area Congruence Postulate
If two figures are congruent, then the have the same
area.
Areas of Rectangles
Area Addition Postulate
The area of a region is the sum of the areas of its nonoverlapping parts.
Areas of Rectangles
Theorem
The area of a rectangle equals the product of its base and
height.
A = bh
Areas of Rectangles
Classify each statement as True or False.
1. If two figures have the same area, then they must be
congruent.
2. If two figures have the same perimeter, then they must
have the same area.
3. If two figures are congruent, then they must have the same
area.
4. Every square is a rectangle.
5. Every rectangle is a square.
6. The base of a rectangle.
Areas of Rectangles
Classify each statement as true or false.
1. If two figures have the same area, then they must be
congruent. False
2. If two figures have the same perimeter, then they must
have the same area. False
3. If two figures are congruent, then they must have the same
area. True
4. Every square is a rectangle. True
5. Every rectangle is a square. False
6. The base of a rectangle. True
Written Exercises
Problem Set 11.1, p.427: # 2 - 20 (even);
Handout 11-1