|| Print ||
Name
LESSON
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
ⴝ
ⴙ
ⴝ
ⴙ
ⴝ
cm
ⴝ
in.
ⴙ
ⴙ
ⴙ
1
Area of Triangle ⴝ ᎏ2ᎏ 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
ⴝ ᎏ2ᎏ bh
1
ⴝ ᎏ2ᎏ ⴛ
1
ⴝ ᎏ2ᎏ ⴛ
R
4 in.
P
ⴛ
ⴝ
Q
20 in.
in2
y
4. In triangle ABC:
base AC ⴝ 10 ⴚ 3 ⴝ
units
height BH ⴝ 4 ⴚ (ⴚ2) ⴝ
8
units.
4
B (5, 4)
Area of triangle ABC
x
1
ⴝ ᎏ2ᎏ ⴛ base AC ⴛ height BH
1
ⴝ ᎏ2ᎏ ⴛ
1
ⴝ ᎏ2ᎏ ⴛ
ⴚ8
ⴛ
ⴝ
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
units2
ⴚ4
O
A
H
(3,ⴚ2)
ⴚ4
(5,ⴚ2)
C (10, ⴚ2)
ⴚ8
21
Holt Pre-Algebra
Holt Middle
School Math
|| Print ||
Name
Date
Class
Reteach
LESSON
6-2 Perimeter and Area of Triangles and Trapezoids (continued)
1
Area of Trapezoid ⴝ ᎏ2ᎏ h(b1 ⴙ 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
ⴝ ᎏ2ᎏ h(b1 ⴙ b2)
1
ⴝ ᎏ2ᎏ h(b1 ⴙ b2)
1
ⴝ ᎏ2ᎏ ⴛ
ⴝ
ⴛ(
ⴛ(
ⴙ
)ⴝ
1
ⴝ ᎏ2ᎏ ⴛ
)
ⴝ
cm2
ⴛ(
ⴛ(
ⴙ
)ⴝ
)
in2
7. In trapezoid PQRS:
base SR ⴝ 8 ⴚ 4 ⴝ
units
base PQ ⴝ 11 ⴚ 2ⴝ
units
height SH ⴝ 6 ⴚ 2 ⴝ
units.
10
y
8
S (4,6)
6
Area of trapezoid PQRS
R (8,6)
1
ⴝ ᎏ2ᎏ ⴛ height SH ⴛ (base SR ⴙ base PQ) 4
1
ⴝ ᎏ2ᎏ ⴛ
ⴛ(
ⴝ
ⴛ(
ⴝ
units2
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
ⴙ
2
)
)
O
22
P (2,2)
2
H (4,2)
4
6
Q (11,2)
x
8
10
Holt Pre-Algebra
Holt Middle
School Math