Question

the area of circle is 78.57m² . it's diameter will be​

Answer 1

$\underline \bold \red{Thanks \: for \: your \: question} \\ \\ \bold \blue{Given :} \\ \\ → Area \: of \: circle = 78.57 \: {m}^{2} \\ \\ → Area \: of \: circle = \pi r {}^{2} \\ \\ \bold \red{</p><p>Solution :} \\ \\ = > \pi r {}^{2} = 78.57 \\ \\ = > \frac{22}{7} \times r {}^{2} = 78.57 \\ \\ = > r {}^{2} = \frac{78.57 \times 7}{22} \\ \\ = > r {}^{2} = \frac{549.99}{22} \\ \\ = > r {}^{2} = \frac{550}{22} \\ \\ = > r {}^{2} = 25 \\ \\ = > r = \sqrt{25} \\ \\ = > r = \bold{5 \: cm \: } \\ \\ Therefore , \: \\ \\ Radius = 5 cm \\ Diameter = 2 × r \\ = > 2 \times 5 = \bold \red{10} \: cm$

Answer 2

Question :-

• The area of circle is 78.57m² . It's diameter will be?

Answer :-

• 10m

Given :-

• Area of circle = 78.57m²

To Find :-

• Diameter of the circle

Using Formula :-

• Area of circle = πr²
• Diameter = Radius × 2

Solution :-

• $\mapsto$$\sf{Area \: of \: circle \: = \: 78.57m^2}$

• $\mapsto$$\sf{\pi r^2 \: = \: 78.57m^2}$

• $\mapsto$$\sf{\dfrac{22}{7} \times r^2 \: = \: 78.57m^2}$

• $\mapsto$$\sf{r^2 \: = \: \dfrac{78.57 \times 7}{22}}$

• $\mapsto$$\sf{r^2 \: = \: \dfrac{549.99}{22}}$

• Doing Round off of 549.99 we get,

• $\mapsto$$\sf{r^2 \: = \: \cancel\dfrac{550}{22}}$

• $\mapsto$$\sf{r^2 \: = \: 25}$

• $\mapsto$$\sf{r \: = \sqrt{25}}$

• $\mapsto$$\sf\pink{r \: = \: 5m}$

• $\mapsto$$\sf{Diameter \: = \: Radius \times 2}$

• $\mapsto$$\sf{Diameter \: = \: 5 \times 2}$

• $\mapsto$$\sf\green{Diameter \: = \: 10m}$

Final Answer :-

• $\sf\bigstar \red{Diameter \: = \: 10m}$