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9.19.2.notebook
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November 18, 2015
Today's objectives:
• Review area formulas that you have previously learned
Chapter 9 Notes
Let's start off with 3 definitions.
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Area
The measure of the region enclosed by a figure.
Base of a rectangle (or parallelogram):
Any side of a rectangle or parallelogram.
Example:Base does not mean bottom!
base
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Altitude of a rectangle (or parallelogram):
A segment perpendicular to the base with one endpoint on the base and the other endpoint on the opposite side.
Examples:
Height of a rectangle (or parallelogram):
Length of an altitude.
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Find the area and perimeter of this figure.
A = _______
P = _______
Approximate the area of this figure.
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Find the area of this figure.
C81
The area of a rectangle is given by the formula A=bh.
(where A is the area, b is the length of the base, and h is the height of the rectangle)
AKA: Rectangle Area Conjecture
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Find the area of the rectangle below.
5 cm
8 cm
2 in
10 in
Find the area of the rectangle below.
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If the area of this rectangle is 84 in2, what is the height?
7 in
4 cm
7 cm
How can we find the area?
4 cm
7 cm
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C82
The area of a parallelogram is given by the formula A=bh.
(where A is the area, b is the length of the base, and h is the height of the parallelogram)
AKA: Parallelogram Area Conjecture
Examples:
12 ft
10 ft7 ft
17 cm
4 6
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15 cm
If the perimeter of this rectangle is 46 cm, find the area.
9.2 Notes
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Find the area of this triangle.
Find the area of this triangle.
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Area of a Triangle
The area of a triangle is given by the formula
(where A is the area, b is the length of the base, and h is the height of the triangle.)
15 cm
4
Draw the altitude and then find the area of the triangle.Show work and give units.
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The altitude of this triangle is 4 inches, and the base is 6 inches. Label these and then find the area of the triangle.
Find the area of the triangle.
5 cm
3
6 cm5.5 cm
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Trapezoids
Altitude of a trapezoid: A segment that is perpendicular to both bases.
The height of the trapezoid is the length of the altitude.
Find the area of this trapezoid.
h
b1
b2
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Area of a Trapezoid
C84 The area of a trapezoid is given by the formula
(where A is the area, b1 and b2 are the lengths of the two bases, and h is the height of the trapezoid)
Find the area of the trapezoid.
10 ft
5
6 ft
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4 cm
h
8 cm
If the area of the trapezoid is 18 cm2, find the height.
8 ft5
12 ft
Find the area of the trapezoid.
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Find the area of this kite.
Find the area of this kite.
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Area of a Kite
C85 The area of a kite is given by the formula
(where A is the area and d1 and d2 are the FULL lengths of the two diagonals)
Find the area of the kite.
4 cm4 cm
2
9
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The area of this kite is 30 cm2. Find d2.
8 2
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Homework for Monday:(These are the same as what is listed
on your assignment sheet.)
9.1 9.2p. 436 p. 439#2-24 even, 25-29 odd #1-19 odd, 25-28 all
and chapter 8 review worksheet!
