question_answer

If the area of circle is 38. 5\[c{{m}^{2}}\], Find its circumference.

Answer:

Area of circle \[=\pi {{r}^{2}}\] \[\pi {{r}^{2}}=38.5\text{ }c{{m}^{2}}\] \[\frac{22}{7}{{r}^{2}}=38.5\]                                                                                                                          \[\pi {{r}^{2}}\text{= }\frac{38.5\times 7}{22}\] \[{{r}^{2}}=12.25\] r = 3.5 cm                                                                                                                     Circumference = 2\[\pi {{r}^{2}}\] \[=2\times \frac{22}{7}\times 3.5\] = 22 cm