Question

Find the diameter of a circle if its area isa. 100cm2Ibucm2c. 400mcm2d. - ncm24​

Answer 1

Answer:

$Diameter = 11.28$cm  --- (a)

$Diameter =22.58$ cm  --- (c)

Step-by-step explanation:

Only (a) & (c) are clear enough to be solved. Others are not properly presented.

Use the following explanations of (a) & (c) to answer others.

$a.\ Area = 100cm^2$

Area is calculated as:

$Area = \pi r^2$

Substitute 100 for Area

$100 = \pi r^2$

Take π as 3.14. So, the expression become

$100 = 3.14 r^2$

Divide both sides by 3.14

$\frac{100}{3.14} = \frac{3.14 r^2}{3.14}$

$\frac{100}{3.14} = r^2$

$r^2 = \frac{100}{3.14}$

$r^2 = 31.847133758$

Solve for r

$r = \sqrt{31.847133758$

$r = 5.64$

But diameter = 2 * radius

So:

$Diameter = 2 * 5.64$

$Diameter = 11.28$

$a.\ Area = 400cm^2$

Area is calculated as:

$Area = \pi r^2$

Substitute 400 for Area

$400 = \pi r^2$

$400 = 3.14 r^2$

Divide both sides by 3.14

$\frac{400}{3.14} = \frac{3.14 r^2}{3.14}$

$\frac{400}{3.14} = r^2$

$r^2 = \frac{100}{3.14}$

$r^2 = 127.388535032$

Solve for r

$r = \sqrt{127.388535032$

$r = 11.29$

But diameter = 2 * radius

So:

$Diameter = 2 * 11.29$

$Diameter =22,58$