Answer:

(i) 132 cm

(ii) 42cm

Step-by-step explanation:

Given, d (diameter) = 42cm , r (radius) = d/2 = 21cm

Perimeter of a circle = Circumference

Therefore, circumference = 2[tex]\pi[/tex]r = 2 × [tex]\frac{22}{7}[/tex] × 21 = 132cm

If  the perimeter of the circle is doubled, then

circumference = 2 × 132 = 264 cm

⇒ 2πr' = 264 cm                        { r' = radius of new circle }

⇒ 2 × [tex]\frac{22}{7}[/tex] × r' =  264 cm

⇒  r' = 42cm