Question

Salma wants to put a lace on the edge of a circular table cover of diameter
 1.5m.Find the length of the lace required and also find its cost if one meter of the lace costs
 Rs.15(Take $\pi = 3.14$ ).

Answer 1

Hint: Since the lace has to be put on the edge of a circular table ,the edge of the circular table is nothing but the circumference of the circle. Let's make use of the formula of circumference of the circle and solve it.

The diameter of the circular table is given as:1.5m
Circumference of the circle is given by the formula=$2\pi r$
Let's find out the value of radius of the circle=$\dfrac{{diameter}}{2} = \dfrac{{1.5}}{2}$
Lets substitute the value of radius in formula of circumference of circle
So we get ,circumference =$2 \times 3.14 \times \dfrac{{1.5}}{2} = 4.71$m
So, the length of required lace=4.71m
Now , the cost of 1m lace is given as=Rs.15
The cost of 4.71m lace required the cover the edge of table cover=$15 \times 4.71$=Rs.70.65
The total length of the lace required to cover the edge of circular table=4.71m
The cost of the lace needed to cover the table=Rs.70.65
Note: When finding the circumference of the circle, if diameter is given make sure to find out the value of the radius before substituting it in the formula of circumference of the circle.