Page 191 - Math Genius C4

E:\Working\Orange_Education\Math_Genius_4\Open_Files\Chap-10
\\September 30, 2025 9:51 AM Bharat Arora P-9 Reader _________________________ Date: ___________________74

Look at the adjoining figure, P
To find the perimeter of such figures, we need a string and a ruler.

Step 1: Start from a point, say P on the curved boundary and put
a string around the boundary till you come back to the
starting point.

Step 2: Measure the length of the string with a
ruler. The total length of the string along activity
this boundary gives the perimeter of the Take a bangle from Experiential Learning

curved figure. your mother and
find its perimeter using a piece
of thread and a ruler. What is
0 cm 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
the perimeter of the bangle?
0 1 2 3 4 5 6 ________________

Practice time 10a

1. Find the perimeter of each of the following figures by counting unit lengths
of squares.

(a) (b) (c)

(d) (e) (f)

2. Find the perimeter of the given figures:
(a) (b) 8 cm (c) 4 cm

5 cm 6 cm 5 cm 5 cm
4 cm 4 cm

8 cm
8 cm
4 cm

(d) 9 m C (e) A 5 cm B (f) B 6 cm C
D 7 m 4 cm 3 cm 4 cm 3 cm
C
5 m 3 cm F D
A 10 m B E 5 cm D A 3 cm 4 cm 5 cm
F

Mathematics-4 189