This document discusses technical drafting and calculating the volume and cost of lumber. It covers measuring the dimensions of lumber, including length, width, and thickness. The unit of measure for volume is the board foot. The formula for calculating board feet is provided as board feet = thickness x width x length / 12. Examples are given to demonstrate calculating the board feet and cost of lumber using the price per board foot. Key concepts are summarized, including that length, width, and thickness are the dimensions used and board foot is the unit of measure.

1. TECHNICAL
DRAFTING

2. Review

3. Review: Identify the tool

4. Review: Identify the tool

5. Review: Identify the tool

6. Review: Identify the tool

7. Review: Identify the tool

8. Pre - Test
Multiple Choice: Choose the correct answer among the
choices. Write the letter of answer on notebook.

9. 1. What are the dimensions measured
to find the volume of a lumber?
A. length, width, and thickness
B. base, length, and height
C. base and height
D. area and height

10. 2. Which of the following is the unit of measure
for determining the volume of lumber?
A. Board foot
B. Cubic feet
C. Cubic meter
D. Square meter

11. 3. If the formula of the volume of a lumber is
Bd.ft.=(T x W x L) / 12; then how many board
feet are there in a lumber with a thickness of 2”,
width of 12”, and length of 1’?
A. 1 Bd.ft. C. 3 Bd.ft.
B. 2 Bd.ft. D. 4 Bd.ft.

12. 4. Compute the board feet of lumber with
dimensions of 2”x2”x6’. The answer would
be ____.
A. 2 Bd.ft. C. 6 Bd.ft.
B. 4 Bd.ft. D. 8 Bd.ft.

13. 5. If you need to buy 2 pieces of lumber
with 2”x2”x6’ dimensions, how much would
you pay if those are sold in 30 pesos per
board foot?
A. 30 pesos C. 90 pesos
B. 60 pesos D. 120 pesos

14. ANSWERS
1. A
2.A
3.B
4.A
5.D

15. Lesson Objectives:
At the end of the lesson, you are able to:
• determine length, width, and thickness of materials;
• compute the board feet of given materials; and
• appreciate the importance of calculating costs of
materials especially as a customer or as an entrepreneur.

16. Common Vocabulary:
• Volume- the amount of space that an object occupies.
• Length- the measurement of something from end to end; the greatest of
three dimensions of a body.
• Width- the measurement of something from side to side.
• Thickness- the distance between opposite sides of something.
• Board foot- a unit of volume for lumber; one board foot is equal to one foot
long by twelve inches wide by one inch thick.

17. Presenting example of the lesson
What figure is this?
How is the volume of this be calculated?

18. Presenting example of the lesson
What figure is this?
How is the volume of this be calculated?

19. Discussion
The dimensions of lumber:
• Length (L) in feet
• Width (W) in inches
• Thickness (T) in inches

20. Discussion
How to calculate the board foot using the formula:
Board Foot (Bd.ft.) = T x W x L
12
Where:
T = Thickness in inches
W = Width in inches
L = Length in feet
Thus,
1”x12”x1’ = 1 bd.ft.
12

21. Example:
How many board feet are there in a lumber with a thickness of 2”, width of 12”, and length of 1’?
Steps 1. Identify the given data
Given. T = 2”
W = 12”
L = 1’
Step 2. Determine what is being asked
Find the Bd. Ft. = ?
Step 3. State the formula
Formula:
Bd. Ft. = T x W x L
12

22. Step 4. Substitute the given data in the formula, then solve.
Solution:
Bd.ft. = T x W x L
12
Bd.ft. = 2” x 12” x 1’
12
= 24/12
= 2 Bd.ft.

23. Discussion: How to calculate the cost of lumber.
Example:
Mang Juan wants to repair the windows in his bedroom. He needs 3 pieces of 2”x3”x4’
wood. How much does it cost if the price of fine wood is 60 pesos per board foot?
Step 1: Identify the given data
Wood: T = 2”
W = 3”
L = 4’
Pieces of wood needed: 3
Price per board foot: 60 pesos

24. Step 2: Determine what is being asked?
Cost of material = ?
Step 3: Calculate the board foot
Bd.ft. = T x W x L x number of pieces
12
Bd.ft. = 2” x 3” x 4’ x 3 pieces
12
= 2 bd.ft x 3
= 6 bd.ft.

25. Step 4: Compute for the cost of material
Cost of Lumber = Total Bd.ft x price per bd.ft.
= 6 bd.ft. x 60 pesos per bd.ft.
= 360 pesos

26. Activity
 Groupings
Each group will be given activity sheet with Problem
Solving task.
Follow the steps and answer correctly.
Do the activity within 5 minutes only.

27. Activity
Performance Checklist
Indicators Yes No
1. Identified the thickness, width, and length correctly.
2. Calculated the volume of lumber in bd.ft.
3. Computed the cost of materials accurately.
4. Completed task within specified TIME.
5. DISCIPLINE is observed in doing tasks.
Score Performance Grade
5 Outstanding 100
4 Very Satisfactory 95
3 Satisfactory 90
2 Unsatisfactory 85
1 Poor 80

28. Key Concepts
• Thickness, Width, and Length are the dimensions measured in finding the
volume of lumber.
• Board foot is the unit of measure for determining the volume of lumber.
• Bd.ft. = T” x W” x L’
12
• Cost of Lumber = Total Bd.ft x price per bd.ft.

29. Post - Test
Multiple Choice: Choose the correct answer among the
choices. Write the letter of answer on notebook.

30. 1. What are the dimensions measured
to find the volume of a lumber?
A. area and height
B. base and height
C. base, length, and height
D. length, width, and thickness

31. 2. Which of the following is the unit of measure
for determining the volume of lumber?
A. Square meter
B. Cubic meter
C. Cubic feet
D. Board foot

32. 3. If the formula of the volume of a lumber is
Bd.ft.=(T x W x L) / 12; then how many board
feet are there in a lumber with a thickness of 2”,
width of 12”, and length of 1’?
A. 4 Bd.ft. C. 2 Bd.ft.
B. 3 Bd.ft. D. 1 Bd.ft.

33. 4. Compute the board feet of lumber with
dimensions of 2”x2”x6’. The answer would
be ____.
A. 1 Bd.ft. C. 3 Bd.ft.
B. 2 Bd.ft. D. 4 Bd.ft.

34. 5. If you need to buy 2 pieces of lumber
with 2”x2”x6’ dimensions, how much would
you pay if those are sold in 30 pesos per
board foot?
A. 30 pesos C. 90 pesos
B. 60 pesos D. 120 pesos

35. ANSWERS
1. D
2.D
3.C
4.B
5.D

36. Assignment:
Essay Writing
Guide questions:
• What are your insights about the lesson?
• Why do measurements important?
• Why do we need to compute for the costs of materials?

37. Thank You!
Prepared by:
JOCELYN B. MIRASOL
Teacher I