RRB Group D Model Paper 6 with solutions

(3) If the diameter of circle is doubled, its radius will also get double. Initially the area of circle = π${\mathit{r}}^2$
Area of circle after doubling its diameter = π${\left(2\mathit{r}\right)}^2$ = 4 π${\mathit{r}}^2$
∴ Area will become 4 times when the diameter is doubled.