Question

4. Neha divides a circular dise of radius 4,2 cm into
two equal parts. What is the perimeter of each
semicircular dise?​

Answer 1

Answer:

21.6cm

Step-by-step explanation:

Perimeter=2r+1/2 2πr

=2r+πr

=2(4.2)+22/7(4.2)

=8.4+13.2

=21.6cm

Answer 2

Answer:108 cm

Step-by-step explanation:

Circle

If radius=42 cm diameter =84cm

Cut into two halves

So now radius of each semicircle=21 cm and diameter=42cm

Now perimeter of a semicircle =22/7 r +d

So perimetwr of the semicircles =(22/7 ×21)+42

So,perimeter =66+42=108cm