Chapter 1 Problems, Problem # 1.2 (Find the area of rectangular plate having length 21.3 ± 0.2 cm and with 9.80 ± 0.10 cm.)

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Class XI / HSC-Ι丨Chapter # 1丨Problems

Problem # 1.2

Calculate

(a)  the circumference of circle of radius 3 cm

                and

(b) area of circle of radius 4.65 cm.

Solution

(a) Circumference of the circle.

Data:

Radius = r = 3.5 cm

Formula

Circumference of the circle = 2πr

C= 2 (3.147)( 3.5)

C= 21.994

 

After reducing

C = 22.0 cm

(b) Are of the circle:

Data:

Radius = r = 4.65 cm

Formula

Area of the circle = πr²

A = (3.147)( 4.65) ²

A = (3.147)( 21.6225)

A = 67.929

After reducing

A= 67.93 cm²