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Name
LESSON
4
Click Here
Date
Class
Reteach
6-2 Perimeter and Area of Triangles and Trapezoids
To find the perimeter of a figure, add the lengths of all its sides.
Complete to find the perimeter of each figure.
1.
2.
C
6 cm
12 in.
M
L
8.2 cm
A
8 in.
B
12.4 cm
J
9 in.
K
6 in.
Perimeter of triangle ABC
Perimeter of trapezoid JKLM
cm
in.
1
Area of Triangle 2 bh
The area of a triangle is one-half the
product of a base length b and the
height h drawn to that base.
h
b
Complete to find the area of each triangle.
3. Area of triangle PQR
1
2 bh
1
2 1
2 R
4 in.
P
Q
20 in.
in2
y
4. In triangle ABC:
base AC 10 3 units
height BH 4 (2) 8
units.
4
B (5, 4)
Area of triangle ABC
x
1
2 base AC height BH
1
2 1
2 8
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All rights reserved.
units2
4
O
A
H
(3,2)
4
(5,2)
C (10, 2)
8
21
Holt Middle School Math
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Name
Date
Class
Reteach
LESSON
6-2 Perimeter and Area of Triangles and Trapezoids (continued)
1
Area of Trapezoid 2 h(b1 b 2 )
The area of a trapezoid is one-half the
height h times the sum of the
base lengths b1 and b2.
b1
h
b2
Complete to find the area of each trapezoid.
5.
Z
6.
5 cm Y
15 in.
9 in.
8 cm
K
W
M
11 in.
N
11 cm
L
23 in.
X
Area of trapezoid WXYZ
Area of trapezoid KLMN
1
2 h(b1 b2)
1
2 h(b1 b2)
1
2 (
(
)
1
2 )
cm2
(
(
)
)
in2
7. In trapezoid PQRS:
base SR 8 4 units
base PQ 11 2
units
height SH 6 2 units.
10
y
8
S (4,6)
6
Area of trapezoid PQRS
R (8,6)
1
2 height SH (base SR base PQ) 4
1
2 (
(
units2
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All rights reserved.
2
)
)
O
22
P (2,2)
2
H (4,2)
4
6
Q (11,2)
x
8
10
Holt Middle School Math
MSM04G8_RESBK_Ch06_123-147
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3/12/03
12:15 PM
Page 126
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Practice C
6-2 Perimeter and Area of Triangles and Trapezoids
Practice B
6-2 Perimeter and Area of Triangles and Trapezoids
LESSON
LESSON
Graph and find the area of each figure with the given vertices.
Find the perimeter of each figure.
1.
2.
C
1
R
5.6
6
5.6
R
C
7.7
3
35
52
K
D
1. (1, 2), (1, 2), (3, 4), (3, 4)
A 3 D
1
8
24
3.
A 3.9 B
12 units
y
4
2
2
P
7
x
1
1
164 units
191
units
0
22.8 units
4
O
2
2
Graph and find the area of each figure with the given vertices.
4. (1, 3), (4, 3), (4, 4), (4, 4)
4
5. (1, 2), (4, 2), (4, 2)
y
y
4
Find the area of each figure with the given dimensions.
2
2
O
2
x
4
4
2
O
2
2
2
4
4
45.5 units2
5. trapezoid: b1 15.2, b2 7.16, h 14.5
4
689 units2
x
4
5
4. triangle: b 103, h 126
4
2
4
2
4
2
162.11 units2
7
3
2
6. trapezoid: b1 98, b2 54, h 63
1
2
7. triangle: b 20.5, h 17.64
52 12 units
180.81 units2
8. The area of a trapezoid is 780 cm2. The shorter base is 48 cm
and the height is 15 cm. Find the length of the other base.
56 cm
16 units2
1
2
9. Find the height of a triangle with area 853 ft2 and base 103 ft.
1
6. Find the area of a triangle with height 16 cm and base 123 cm.
2
2
16 ft
98 cm
3
10. Find the length of each side of a triangle if the perimeter is
73 in. The length of the second side is twice the length of the
first side and the length of the third side is five more than the
length of the first side.
7. Find the area of a trapezoid with height 20.4 in. and bases
14.4 in. and 9.7 in.
245.82 in2
first side 17 in.; second side 34 in.; third side 22 in.
8. Find the height of a trapezoid with area 96 m2 and bases 13 m
and 19 m.
6m
19
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
Holt Middle School Math
LESSON
To find the perimeter of a figure, add the lengths of all its sides.
1
Area of Trapezoid 2 h(b1 b 2 )
The area of a trapezoid is one-half the
height h times the sum of the
base lengths b1 and b2.
Complete to find the perimeter of each figure.
2.
C
6 cm
12 in.
M
L
8.2 cm
A
b1
h
b2
Complete to find the area of each trapezoid.
8 in.
B
12.4 cm
Holt Middle School Math
Reteach
6-2 Perimeter and Area of Triangles and Trapezoids (continued)
Reteach
6-2 Perimeter and Area of Triangles and Trapezoids
LESSON
1.
20
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
9 in.
5.
Z
6.
5 cm Y
K
6 in.
Perimeter of triangle ABC
12.4
26.6
cm
8.2
K
Perimeter of trapezoid JKLM
6
6
35
in.
9
12
W
8
1
Area of Triangle 2 bh
The area of a triangle is one-half the
product of a base length b and the
height h drawn to that base.
h
Area of trapezoid WXYZ
Area of trapezoid KLMN
1
2 h(b1 b2)
1
2 h(b1 b2)
b
1
2 80
40
P
units
6
1
2 8
units.
4
B (5, 4)
Area of triangle ABC
x
1
2 base AC height BH
1
2 7
6
1
2 42
21
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All rights reserved.
8
units2
(
16
)
64
1
)
2 2
cm
4.5
9
(
11
(
34
)
153
23
)
2
in
4
4
9
4
units
10
y
units
8
units.
S (4,6)
6
R (8,6)
1
2 height SH (base SR base PQ) 4
y
height BH 4 (2) 11
Area of trapezoid PQRS
in2
7
height SH 6 2 Q
20 in.
4. In triangle ABC:
base AC 10 3 5
base PQ 11 2
4 in.
4
(
base SR 8 4 R
1
2 bh
4
8
7. In trapezoid PQRS:
3. Area of triangle PQR
20
L
23 in.
X
11 cm
1
2 Complete to find the area of each triangle.
1
2 15 in.
9 in.
8 cm
M
11 in.
N
J
2
26
4
(
(
13
4
9
2
)
)
O
P (2,2)
2
H (4,2)
4
6
Q (11,2)
x
8
10
units2
O
A
H
4 (3,2) (5,2)
C (10, 2)
8
21
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
Holt Middle School Math
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
126
22
Holt Middle School Math
Holt Middle School Math