PA GOVERNOR’S INSTITUTE--2005
Calculate Perimeter
Math-in-CTE Lesson Plan
Lesson Title: Calculate Perimeter of Machined Part
Lesson Number: 29
Occupational Area: Drafting Design
CTE Concept(s): Calculate Perimeter
Math Concepts: Formula for Finding the Perimeter of a Rectangular Machined Part
Lesson Objective:
Supplies Needed:
Student will demonstrate the ability to calculate the perimeter of a rectangular machined part.
Scale, Pencil, Machine Part/Drawing,
TEACHER NOTES
(and answer key)
THE "7 ELEMENTS"
1. Introduce the CTE lesson.
Today we are going to talk about how to calculate the perimeter of
machined part.
Distance around the outside of an object we are making
or building.
What does perimeter mean?
Example: Distance around a football field.
Siding on a house.
2. Assess students’ math awareness as it relates to the CTE lesson.
Can anyone think of a place where you would use this concept in real
life?
Fence around a yard, Building a deck, Concrete
sidewalk.
3. Work through the math example embedded in the CTE lesson.
Let’s say we have a rectangular machined part that is 2” long by 6” Perimeter = 2 (Length + Width)
wide. What would the perimeter be?
Or you can obtain the perimeter of any object by adding
together the distances of all sides.
Perimeter = 2 (2” + 6”)
Perimeter = 2(8”)
Perimeter = 16”
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PA GOVERNOR’S INSTITUTE--2005
Calculate Perimeter
What happens if we use millimeters for the unit of dimensions instead of 25.4 mm = 1 “
inches for the same part?
2” = 50.8 mm
6” = 152.4 mm
Perimeter = 2(50.8mm + 152.4mm)
Perimeter = 2(203.2mm)
Perimeter = 406.4 mm
4. Work through related, contextual math-in-CTE examples.
Now we will work on some actual drawings. Using the given drawing
and dimensions calculate the perimeter of the part.
Given a machine part measure and calculate the perimeter.
Would the perimeter change if we cut a ½” wide x ½” deep slot on one
of the longest sides of the rectangular part?
Draw a rectangular part 3.188” by 6.188”
Teacher may use any machine part / rectangular object
available in the classroom.
Yes
It will increase by 1 inch (50.8mm) in each example.
By how much would it change in the example?
5. Work through traditional math examples.
In carpentry you would put crown molding around a perimeter of a
room. How much crown molding would be required for a room that is
9’ by 12’?
How much chair rail would be needed for the same 9’ x 12’ room if it
has two 3’ doors?
42’ of crown molding
36’ of chair rail
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PA GOVERNOR’S INSTITUTE--2005
Calculate Perimeter
6. Students demonstrate their understanding.
What other career field uses the perimeter formula?
Building construction, masonry, welding, landscaping,
Homework assignment – Bring in any geometric shaped object from
home with straight sides.
Have students select a partner and measure and find the
perimeter of each other’s object that was brought in.
Does the formula provided work with a non-rectangle?
No. Other geometric shapes have various formulas that
will be covered in the future.
Perimeter = 2 (Length + Width)
Examples
Perimeter of a Triangle = ½ (base)(height)
Perimeter of a Circle = ! (Diameter)
Can you find the perimeter of this machined part?
This part can come from any available in the room.
Add the length of all sides and cutouts.
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PA GOVERNOR’S INSTITUTE--2005
Calculate Perimeter
7. Formal assessment.
Possible test questions.
1.Find the perimeter of a machined part that is 3.625“ by 5.750”.
Perimeter = 2(3.625 + 5.750”)
= 2(9.375”)
= 18.750”
2.Find the perimeter of a machined part that is 50.8mm by 485.4mm.
Perimeter = 2(50.8mm + 485.4mm)
= 2(536.2mm)
= 1072.4mm
3. Find the perimeter of a machined part that is 4.125” by 5.375”.
Perimeter = 2(4.125 + 5.375”)
= 2(9.5”)
= 19.0”
Perimeter = 2(2.938 + 4.812”)
4. Find the perimeter of a machined part that is 2.938” by 4.812”.
= 2(7.750”)
= 15.50”
5. Find the perimeter of a machined part that is 20mm by 35.5mm.
Perimeter = 2(20mm + 35.5mm)
= 2(50.5mm)
= 101mm
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PA GOVERNOR’S INSTITUTE--2005
Calculate Perimeter
Adaptations for special needs students.
Use whole numbers, Supply calculator, Allow extra time as
needed
Teacher Notes:
Math Standards and Assessment Anchors addressed with this lesson.
M11A1.1, M11B.1, M11B2.2.2, M11B2.2.4
References.
Practical Problems in Mathematics for Drafting and CAD by Dr. John C. Larkin, Machinery’s handbook
Author(s):
David Richards
Paul Livermore
Charleen Keen
Position:
Drafting Design
Assistant Director
Math Instructor
School:
Crawford County AVTS
Crawford County AVTS
Dauphin County Technical School
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