Question 15 Marks
Find the area of a quadrant of a circle hose circumference is 44cm.
Answer
View full question & answer→Let r be the radius of the circle,
Then, circumference of a circle $=2\pi\text{r}$
$\Rightarrow2\pi\text{r}=44$
$\Rightarrow2\times\frac{22}{7}\times\text{r}=44$
$\Rightarrow\text{r}=7\text{cm}$
$\therefore$ Area of the quadrant $=\Big(\frac{1}{4}\times\frac{22}{7}\times7\times7\Big)\text{cm}^2=\frac{77}{2}\text{cm}^2=38.5\text{cm}^2$
Then, circumference of a circle $=2\pi\text{r}$
$\Rightarrow2\pi\text{r}=44$
$\Rightarrow2\times\frac{22}{7}\times\text{r}=44$
$\Rightarrow\text{r}=7\text{cm}$
$\therefore$ Area of the quadrant $=\Big(\frac{1}{4}\times\frac{22}{7}\times7\times7\Big)\text{cm}^2=\frac{77}{2}\text{cm}^2=38.5\text{cm}^2$

Let A, B, C, D be the centres of these circles



OP = OR = OQ = r













Ungrazed area



Shaded area = (area of quadrant) - (area of DAOD)

Required area = [area of square - areas of quadrants of circles]




Let A, B, C, be the centres of these circles. joint AB, BC, CA
Length of the inner curved portion







Side of square = 28cm and radius of each circle $=\frac{28}{2}\text{cm}$
PS = 12cm