The document discusses different measuring instruments used in technical drafting and their purposes. It lists common measuring tools like the compass, divider, protractor, triangles, T-square, ruler, tape ruler, and triangular scale. The document also provides examples of unit conversion calculations between millimeters and centimeters, and inches and meters.

1. TECHNICAL DRAFTING 8
QUARTER 3 – WEEK 4
PERFORM
BASIC
MENSURATIO
N AND
CALCULATION

2. LEARNING OUTCOME:
LO 1. Select measuring instruments
LO 2. Carry out mensuration and
calculation

3. In your own personal opinion,
what do you think is the importance
of measuring tools?

4. DIFFERENT MEASURING
INSTRUMENTS

5. used to draw
circles, arcs,
radii, and parts
of many symbols
used for dividing
distances into a
number of equal
parts by the
trial-and-error
method.
used for measuring and
setting angles other
than those obtainable
with the triangles.
COMPASS DIVIDER
PROTRACTOR

6. T
R
I
A
N
G
L
E
S
T-SQUARE RULER
used for drawing vertical
and oblique lines. The 45°
and the 30° x 60° are the
most commonly used.
used as a guide in
drawing horizontal
lines and in
measuring up to
48” straight lines.
is usually 6 or 12 inches in
length. It is needed for
measuring sizes and
distances.

7. TRIANGULAR
SCALE
TAPE RULER
a concave, spring-steel blade
ranging from 1/4" to 1" wide
and 6 to about 300 feet in
length, coiled inside a carrying
case
main purpose is to
reproduce the
dimension in full
size or to reduce or
enlarge them on a
drawing

8. SYSTEM OF
MEASUREMENTS

17. EXAMPLE :
If 10 mm = 1 cm
Then 13 mm = __________ cm
13 mm x
10 mm
1 cm
=
13 cm
10
= 1.3 cm
If 1 in = 0.0254 m
Then 2.5 in = __________ m

18. EXAMPLE :
2.5 in x
1 in
0.0254 m
=
0.0635 m
1
= 0.0635 m
If 1 in = 0.0254 m
Then 2.5 in = __________ m