A powerpoint presentation about the lesson "Measurement" (geometry)

1. Measurement
Perimeter
&
Circumference

2. Perimeter Circumference
distance
vs
around a POLYGON around a CIRCLE

3. Let us start with a PERIMETER…
Sir
wait….!
?????
OMG…. Ano
tana ang
ginawakal ni
sir nga
PERIMETER
man?

4. PERIMETER
- refers to the
distance around
a polygon, it is
the sum of the
lengths of its
side.
How can we find the PERIMETER
of a polygon?

5. Jonnel Palanog plans to put a ribbon at
the edge of his bed sheet. The length of
the bed sheet is 4 meters and a width of
2 meters. How many meters of ribbon
does he needs?

6. Illustration
4 m
l
l
ww 2 m
The total length of ribbon that Jonnel needs can
be determined by adding the measures of the
sides of the polygon (rectangle).

7. Perimeter (P) = 4m + 2m + 4m + 2m = 12m
Jonnel needs 12 meters to put the intire edge of
his bed sheet.
If l represents the length and w represents the width of
a rectangle, then
P = l + w + l + w
= l + l +w + w
P = 2l + 2w
l
l
ww

8. Example
Find for the perimeter of a rectangular
glass table: l = 4m, w = 2m
P = 2l + 2w
= 2(4m) + 2(2m)
= 8m + 4m
P = 12m

9. Trapezoid
P = 2 cm + 3 cm
+ 2 cm + 5 cm
P = 12 cm P = a + b + c + d
3 cm
5 cm
2 cm2 cm
If a, b, c, d represent the
length of the sides of
the trapezoid, then
a
d
cb

10. Example
Find for the perimeter of a regular
pentagonal table whose side is 7m
Regular pentagon has 5 congruent sides.
P = s + s + s + s + s
P = 5s
= 5 (7m)
P = 35m

11. CIRCUMFERENCE
distance
around a
circle
How to find the
circumference of a
circle?

12. d
C

13. d
C
Derive …..
π=
C
dd
C
In terms of radius rC 2

14. Illustration
Corniel’s bicycle has wheel with
diameter of 60 centimeters. By
how many meters has the
bicycle moved when the wheels
made one revolution?

15. 60 cm
dC
C = 60cm π
C = 60cm (3.14)
C =188.4 cm
C =1.884 meters
Here’s how…

16. Let’s try…
Find the perimeter of the following figures.
All measures are in cm.
5m
9m9m
13m
11cm
11cm
11cm 11cm
7cm
7cm
8mm
14mm
10mm
12mm 9cm

17. Find the circumference. All measures are in
centimeters.
2.76 cm
1.3cm
1. 2.

18. “It is Mathematics that offers the
exact natural sciences a certain
measure of security
which, without mathematics, they
could not attain.”
-Albert Einstein