Areas of Parallelograms & Triangles Tutorial 13b.
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Transcript of Areas of Parallelograms & Triangles Tutorial 13b.
Areas of Parallelograms & Triangles
Tutorial 13b
Parallelograms• You can choose any side of a
parallelogram to be a base. • An altitude is any segment
perpendicular to the line containing the base drawn from the side opposite the base.
• The height is the length of the altitude.
base
height
Area of a Parallelogram
• The area of a parallelogram is the product of any base and the corresponding height.
A = bh
b
h
Area of a Parallelogram
• The area of a parallelogram is the product of any base and the corresponding height.
A = bh
A = 5•3
A= 155
3
8
4
124
A = bhA = 4•8A = 32 units2
A = bhA = 12•4A = 48 units2
2.
8
3. 4.
Find the value of x in each parallelogram below.
A = bhA = 8•4A = 32
Click here to continue
Use one set of base & height to find the area. After knowing the area, use the other base with the unknown height (x) and the area formula to solve for x.
32= bh32= 5x
= x
8
5
32
3. 4.
Find the value of x in each parallelogram below.
A = bhA = 8•4A = 32
5
x
Use one set of base & height to find the area. After knowing the area, use the other base with the unknown height (x) and the area formula to solve for x.
32= bh32= 5x
= x
8
5
32
3. 4.
Find the value of x in each parallelogram below.
A = bhA = 8•4A = 32
5
x
Check Answer
Try #4 on your own, then click below to check your answers.
32= bh32= 5x
= x
8
5
32
3. 4.
Find the value of x in each parallelogram below.
A = bhA = 8•4A = 32
5
x
A = bh A = 19•11 A = 209209= bh209= 12x
= x12
209
Triangles
• You can choose any side of a triangle to be the base.
• The corresponding height is the length of an altitude drawn to the line containing the base.
base
height
Area of a Triangle
• The area of a triangle is half the product of any base and the corresponding height.
bhA2
1
b
h
Example #1
• Find the area of this triangle
bhA2
1
20 ft
6 ftA = 1/2 •20•6A = 60 ft2