Lesson #8 title: PART 8 = APPLYING AREA and PERIMETER to story word problems (& gr5 review)
Date:
THROUGH-LINE: Beauty – creating
Beauty is observed by creating different rectangles (the largest or the smallest) depending on the given P (outside) or the given A (inside).
OUTCOMES:
1. Calculate P of regular polygons using generalized formula.
2. Determine the area and perimeter of a given rectangle, drawn without a grid, using a
mathematical rule. (GR5 POS)
3. Provide a real-life context for when it is important to consider the relationship between area
and perimeter. (GR5 POS)
MATERIAL NEEDED: highlighters, pencil, blue pen
Example #1: Calculate the PERIMETER of a regular nonagon with each side of 17.9 cm.
NONAGON means
equal sides.
FORMULA (EQUATION) with letter variable:
EQUATION with number value:
FINAL ANSWER: P =
Example #2: (obtained from Eduguide6, p.102)
Use an equation to find the perimeter of each of these regular polygons. Assume the given
measurements are in cm. DRAW THE TICKS to show equal sides
FORMULA (EQUATION) with VARIABLE LETTER:
EQUATION with actual number value:
FINAL ANSWER:
GRADE 5 PERIMETER & AREA returns ! 
Example #3: (Obtained from Eduguide5, p.222)
CALCULATE the area and the perimeter for each (not drawn to scale).
Record P & A INSIDE each polygon.
OBSERVATIONS:
GREATEST AREA is rectangle
Example #4:
A person went to Home Depot and bought 30 metres of fencing to build a fence in her rectangular
backyard. What might be the area of her backyard? Draw a rectangle and label the l
the largest area to play in. How do you know that you drew the largest rectangle?
FINAL ANSWERS:
Area of her backyard:
How do you know you have largest rectangle?
and w that would
L8(3)
YOUR TURN  READ CAREFULLY! DRAW SKETCH and label.
#1: (Obtained from MF5 p.266)
VISUALIZE the size and shape of each rectangle based on the length and width. PREDICT which rectangle
will have the greatest area. PREDICT which rectangle will have the greatest perimeter. Why?
a) 3 cm x 12 cm
b) 5 cm x 10 cm
c) 7 cm x 8 cm
My predictions:
GREATEST AREA is rectangle
GREATEST PERIMETER is rectangle
DRAW these three rectangles (use these dimensions).
L8(4)
#2: (Obtained from Eduguide5, p.220)
CALCULATE the area and the perimeter for each (not drawn to scale). LABEL the l
P=
(use formula) A=
and w
P=
(use formula) A=
Draw another rectangle with the SAME PERIMETER as rectangle B above, but SMALLER area (not to
scale). LABEL the l
and w
Draw another rectangle with the SAME AREA as rectangle A above, but GREATER perimeter (not to
scale). LABEL the l
#3:
FINAL ANSWER:
and w
L8(5)
#4:
A
B
Suppose that each rectangle has a perimeter of 100 cm. Which of these two rectangles has the smallest
area? How do you know?
Answer: The smallest area is rectangle
I know this because
Suppose you had a deck off your house. Which of these two rectangles would be the better design?
Explain your thoughts.
Answer: The smallest area is rectangle
I know this because
#5: The two sides of a rectangle are 4.7m and 11.5m. What is the perimeter? Draw and label sketch.
Solve.
A=
FINAL ANSWER:
#4: If you are building a deck, why would it be important to think about the perimeter and the area of your
deck BEFORE you started to build?
L8(6)
#6:
FORMULA (EQUATION) with VARIABLE LETTER:
EQUATION with actual number value:
FINAL ANSWER:
FORMULA (EQUATION) with VARIABLE LETTER:
EQUATION with actual number value:
FINAL ANSWER EQUATION:
FORMULA (EQUATION) with VARIABLE LETTER:
EQUATION with actual number value:
FINAL ANSWER:
#7. The perimeter of a regular hexagon is 52.2 cm. What is the length of one side?
HEXAGON means
FORMULA (EQUATION) with letter variable:
EQUATION with number value:
FINAL ANSWER: P =
equal sides.
#8:
LABEL all sides that have missing dimensions.
CALCULATE the perimeter of this polygon (no equation needed. Just solve).
FINAL ANSWER: P =