Module 4 Lesson 14 Find areas by decomposing into rectangles or completing composite figures to form rectangles
Skip counting Let’s skip count by 4s to 40. 40 32 12 4 8 24 36 20 16 28
Skip counting Let’s skip count by 6s to 60. 60 48 18 6 12 36 54 30 24 42
Skip counting Let’s skip count by 7s to 70. 70 56 21 7 14 42 63 35 28 49
Skip counting Let’s skip count by 9s to 90. 90 72 27 9 18 54 81 45 36 63
Multiply by 8 48 6 x 8 = _______ Let’s skip count UP by 8s to solve. Let’s skip count DOWN by 8s – starting at 80. 8 16 24 32 40 48 80 72 64 56 48
Multiply by 8 64 8 x 8 = _______ Let’s skip count UP by 8s to solve. Let’s skip count DOWN by 8s – starting at 80. 8 16 24 32 40 48 56 64 80 72 64
Multiply by 8 48 9 x 8 = _______ Let’s skip count UP by 8s to solve. 8 16 24 32 40 48 56 64 72 Let’s skip count DOWN by 8s – starting at 80. 80 72
PATTERN SHEET
___ sq. Units + ____ sq. Units = ___ sq. Units Find the area On your white board or notebook, write a number sentence to show the area of the shaded rectangle. 5 x 2 = 10 square units or 2 x 5 = 10 square units Write a number sentence to show the area of the un-shaded rectangle. 3 x 2 = 6 square units or 2 x 3 = 6 square units ___ sq. Units + ____ sq. Units = ___ sq. Units 10 6 16
___ sq. Units + ____ sq. Units = ___ sq. Units Find the area On your white board or notebook, write a number sentence to show the area of the shaded rectangle. 4 x 3 = 12 square units or 3 x 4 = 12 square units Write a number sentence to show the area of the un-shaded rectangle. 2 x 2 = 4 square units or 2 x 2 = 4 square units ___ sq. Units + ____ sq. Units = ___ sq. Units 12 4 16
___ sq. Units + ____ sq. Units = ___ sq. Units Find the area On your white board or notebook, write a number sentence to show the area of the shaded rectangle. 2 x 6 = 12 square units or 6 x 2 = 12 square units Write a number sentence to show the area of the un-shaded rectangle. 2 x 4 = 8 square units or 4 x 2 = 8 square units ___ sq. Units + ____ sq. Units = ___ sq. Units 12 8 20
___ sq. Units + ____ sq. Units = ___ sq. Units Find the area On your white board or notebook, write a number sentence to show the area of the shaded rectangle. 4 x 4 = 16square units or 4 x 4 = 16 square units Write a number sentence to show the area of the un-shaded rectangle. 2 x 2 = 4 square units or 2 x 2 = 4 square units ___ sq. Units + ____ sq. Units = ___ sq. Units 16 4 20
Problem of the day Break apart the shaded figure into 2 rectangles. Then, add to find the area of the shaded figure below. Subtract the area of the unshaded rectangle from the area of the large rectangle to check your answer.
Concept Development – Choose an appropriate Method for Find the Area of a composite shape. What two strategies did we learn last week to find the area of a non-rectangular shape?
19 square centimeters! Make sure everyone has a problem set Look at problem 1(a) What is the unknown Width? Label that on your figure. Then, write an equation used to find the area of each of the smaller rectangles. What is the area of the top rectangle? The bottom rectangle? On your problem set, write the equation to find the area of the whole figure. WHAT IS THE TOTAL AREA? 19 square centimeters!
Problem 2: solve a word problem involving the area of non-rectangular shapes. Sierra has a piece of fabric that is 8 feet long and 5 feet wide. She cuts out a rectangular piece that measures 3 feet by 2 feet. How many square feet of fabric does Sierra have left? Draw and label Sierra’s fabric. How big is the piece that Sierra cuts out? Draw the piece of fabric that Sierra cuts out – don’t forget to label the measurements. (THUMBS UP WHEN YOU’RE DONE) What is the area of the piece that is cut out? What expression tells us the area of the remaining fabric? 40 – 6. How much fabric does Sierra have left? 34 square feet! What is the best way for us to find the area of the remaining fabric? Write an equation to find the area of the original piece of fabric. Beneath what you just wrote write an equation to find the area of the piece of fabric Sierra just cut out.
PROBLEM SET