Page 28 - CITS - WCS - Mechanical

WORKSHOP CALCULATION - CITS

Perimeter (P) = l + 2r unit

18.6 = 1.83r + 2r

3.83r = 18.6 cm
18.6
r = = 4.86 cm
3.83
θ
Area A = x πr² unit²
360°
105° 22
= x x (4.86) cm²
360° 7
= 21.65 cm²

2 Find the area, if the radius is 12.4 cm and the perimeter of a sector of a circle is 64.8 cm.

Given:
Perimeter P = 64.8 cm

Radius r = 12.4 cm
To find:
Area A = ?
Solution:

Perimeter P = l + 2r unit
l = P - 2r unit
= 64.8 - 2 (12.4) cm
= 64.8 - 24.8 = 40 cm

lr 40 x 12.4
Area A = unit² =
2 2
= 248 cm²
3 Find out the length of the belt , if the arrangement of a belt is shown in the figure below. Solution:

θ
Length l = x 2πr unit
A 360°
210° 22
= x 2 x x 30 = 110 cm
360° 7
θ
Length l = x 2πr unit
B 360°

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CITS : WCS - Mechanical - Exercise 5 CITS : WCS - Mechanical - Exercise 5