A circular gift-wrapping paper is having an area of a 154 square cm. What is the radius, diameter and circumference of this circular paper?

Area of circle $= {\mathrm{\pi r}}^2$

$154 = \frac{22}{7} \times \mathrm{r} \times \mathrm{r}$

$1078 = 22 \times r \times r$

$\frac{1078}{22} = \mathrm{r} \times \mathrm{r}$

$49 = \mathrm{r} \times \mathrm{r}$

$49 = {\mathrm{r}}^2$

$\mathrm{r} = \sqrt{49}$

$\mathrm{r} = 7$

The radius of a circle with an Area of 154 is 7 cm.

$\mathrm{Diameter} = 2\times \mathrm{radius}$

$\mathrm{D} = 2 \times 7$

$= 14 \mathrm{cm}$

The circumference of the circle is $2\mathrm{\pi r}$ or $\mathrm{\pi D}$

$\begin{array}{c}= \frac{22}{7}\times 14 \\ = 22 \times 2 \\ = 44 \mathrm{cm}\end{array}$