Lesson 5.3.3 – Area of Trapezoids
Teacher Lesson Plan
Lesson:
5.3.3 – Supplement
Area of Trapezoids
CC Standards
6.G.1
Find the area of right triangles, special quadrilaterals, and polygons by composing into rectangles or
decomposing into triangles and other shapes; apply these techniques in the context of solving real-world
and mathematical problems.
6.G.3
Draw polygons in the coordinate plane given coordinates for the vertices; use coordinates to find the length
of a side joining points with the same first coordinate or the same second coordinate. Apply these
techniques in the context of solving real-world and mathematical problems.
Objective
The students will learn to find the area of trapezoids using a formula. Then they will get repetitive practice on finding
the area of all the shapes we’ve studied so far.
Mathematical Practices
#1 Make sense of problems and persevere in solving them
#7 Look for and make sense of structure
Teacher Input
Bellwork:
Review bellwork.
Homework:
Review previous night’s homework.
Introduction: You may do the explore activity from the CPM textbook, lesson 5.3.3. Whether or not
you choose to do the activity may depend upon the level of your particular class.
Lesson:
Teach according to the student notes.
Extra Practice
Classwork
Page 3
Homework
Page 5
Extra Practice Page 4
Closure
Teacher selected
1|Page
Lesson 5.3.3 – Area of Trapezoids
Student Notes
SETION 1: Defining a Trapezoid
A trapezoid is a quadrilateral with one pair of parallel sides. Notice in the
figure on the right that a trapezoid has two bases which are different lengths. The
two bases are parallel to each other.
The height of the trapezoid must be perpendicular from the top of one base
to the bottom of the other.
Looking at the trapezoid below, the height is a side of the trapezoid since it is perpendicular to the base.
SETION 2: FINDING THE AREA OF TRAPEZOIDS USING A FORMULA
Formula: A = ½ • (b1 + b2) • h
Step 1:
Step 2:
Step 3:
Write down your formula. A = ½ • (b1 + b2) • h
Substitute the information from the trapezoid into the formula.
Perform the operations and write you’re answer in square units.
Let’s try these together.
1)
2)
You Try – Independent Practice
1)
2)
2|Page
Lesson 5.3.3 – Area of Trapezoids
Classwork
Name___________________________ Date__________
Period: ____
Find the area of each trapezoid below. Be sure to show where you write your formula down for each
problem, plug in the number, and write your answer in square units.
1)
2)
3)
4)
5)
6)
3|Page
Lesson 5.3.3 – Area of Trapezoids
Extra Practice
Name___________________________ Date__________
Period: ____
Area Mixed Review
Solve each problem below. Be sure to show where you write your formula down for each
problem, plug in the number, and write your answer in square units.
1)
2)
3)
4)
5)
6)
Which equation correctly shows how to calculate
the distance between point d and point c on the
coordinate plane above?
A. |-5| + |-1|
C. |-4| - |-2|
B. |-5| - |-1|
D. |-5| - |1|
4|Page
Lesson 5.3.3 – Area of Trapezoids
Homework
Name___________________________________
Date__________
Period: ____
Find the area of each shape.
1)
2)
3)
4)
Solve problems 5 and 6 as directed.
5)
6)
What is the area of the parallelogram above?
Which equation correctly shows how to calculate
the distance between point x and point y on the
coordinate plane above?
A. |3| - |-1|
C. |-3| - |-1|
B. |-1| + |-4|
D. |3| +|-1|
5|Page
Lesson 5.3.3 – Area of Trapezoids
6|Page
Lesson 5.3.3 – Area of Trapezoids
Student Notes
Answer Key
SETION 1: Defining a Trapezoid
A trapezoid is a quadrilateral with one pair of parallel sides. Notice in the
figure on the right that a trapezoid has two bases which are different lengths. The
two bases are parallel to each other.
The height of the trapezoid must be perpendicular from the top of one base
to the bottom of the other.
Looking at the trapezoid below, the height is a side of the trapezoid since it is perpendicular to the base.
SETION 2: FINDING THE AREA OF TRAPEZOIDS USING A FORMULA
Formula: A = ½ • (b1 + b2) • h
Step 1:
Step 2:
Step 3:
Write down your formula. A = ½ • (b1 + b2) • h
Substitute the information from the trapezoid into the formula.
Perform the operations and write you’re answer in square units.
Let’s try these together.
2)
A = ½ • (b1 + b2) • h
A = ½ • (8 + 11) • 6
A = 57 in²
2)
A = ½ • (b1 + b2) • h
A = ½ • (6 + 20) • 10
A = 130 cm²
You Try – Independent Practice
2)
A = ½ • (b1 + b2) • h
A = ½ • (4 + 10) • 5
A = 35 cm²
2)
A = ½ • (b1 + b2) • h
A = ½ • (12 + 22) • 12
A = 204 cm²
7|Page
Lesson 5.3.3 – Area of Trapezoids
Name___________________________ Date__________
Period: ____
Classwork
Answer Key
Find the area of each trapezoid below. Be sure to show where you write your formula down for each
problem, plug in the number, and write your answer in square units.
1)
2)
A = ½ • (b1 + b2) • h
A = ½ • (b1 + b2) • h
A = ½ • (20 + 7.6) • 13
A = 179.4 km²
A = ½ • (3 + 7) • 8
A = 40 m²
3)
4)
A = ½ • (b1 + b2) • h
A = ½ • (182 + 267) • 254
A = 57,023 mi²
A = ½ • (b1 + b2) • h
A = ½ • (15 + 8) • 15
A = 172.5 ft²
5)
6)
A = ½ • (b1 + b2) • h
A = ½ • (b1 + b2) • h
A = ½ • (7 + 9) • 4
A = 32 cm²
A = ½ • (5 + 12) • 5
A = 42.5 cm²
8|Page
Lesson 5.3.3 – Area of Trapezoids
Name___________________________ Date__________
Period: ____
Extra Practice
Answer Key
Area Mixed Review
Solve each problem below. Be sure to show where you write your formula down for each
problem, plug in the number, and write your answer in square units.
1)
2)
A=b•h
A = 4.25 • 3.5
A = 14.875 km²
3)
A=b•h
A = 6¼ • 3½
𝟕
A = 21 𝟖 ft²
4)
A=½•b•h
A = ½ • 9 • 18
A = 81 ft²
A=½•b•h
A = ½ • 25½ • 15
𝟏
A = 191 𝟒 ft²
5)
6)
A = ½ • (b1 + b2) • h
A = ½ • (30 + 5) • 100
A = 1,750 in²
Which equation correctly shows how to calculate
the distance between point d and point c on the
coordinate plane above?
A. |-5| + |-1|
C. |-4| - |-2|
B. |-5| - |-1|
D. |-5| - |1|
9|Page
Lesson 5.3.3 – Area of Trapezoids
Name___________________________ Date__________
Period: ____
Homework
Answer Key
Find the area of each shape.
1)
2)
A = ½ • (b1 + b2) • h
A = ½ • (b1 + b2) • h
A = ½ • (6 + 7.9) • 3
A = 20.85 in²
A = ½ • (12 + 18) • 11
A = 165 mm²
3)
4)
A = ½ • (b1 + b2) • h
A =½•b•h
A = ½ • 10 • 10
A = ½ • (8 + 12) • 9
A = 90 cm²
A = 50 units squared
Solve problems 5 and 6 as directed.
5)
6)
Which equation correctly shows how to calculate
the distance between point x and point y on the
coordinate plane above?
A. |3| - |-1|
C. |-3| - |-1|
B. |-1| + |-4|
D. |3| + |-1|
What is the area of the parallelogram above?
A=b•h
A=3•2
A = 6 units squared
10 | P a g e