The length of a rectangular field is 65 meters. Its width is 35 meters. Joni ran around the track 4 times. How far did she run?

Hint: First we will see that the width of a rectangle is 35 m, which is also the breadth of a rectangle. Then we will use the formula of perimeter of a rectangle,\[2\left( {l + b} \right)\], where \[l\] is the length and \[b\] is the breadth to find the length of the field. Then multiply 4 with it to find the required value.

Complete step-by-step answer:
We are given that the length of a rectangular field is 65 meters. Its width is 35 meters.


We know that the perimeter of a rectangle is calculated using the formula,\[2\left( {l + b} \right)\], where \[l\] is the length and \[b\] is the breadth.
Since we are given the width of a rectangle is 35 m, which is also the breadth of a rectangle.
Substituting the value of length and breadth in the above formula of perimeter of a rectangle, we get
\[
   \Rightarrow 2\left( {65 + 35} \right) \\
   \Rightarrow 2\left( {100} \right) \\
   \Rightarrow 200{\text{ m}} \\
 \]
So as Joni runs 4 times, we multiply the above perimeter with 4, we get
\[
   \Rightarrow 4\left( {200} \right) \\
   \Rightarrow 800{\text{ m}} \\
 \]
Thus, Joni used to cover the distance of 800 m by running 4 times around a rectangular field.

Note: In solving these types of questions, students should remember that the perimeter of any shape is the sum of the length of all its sides. And there are four sides in a rectangle out of which opposite sides are equal and adjacent sides are different. And the adjacent sides of the rectangle are known as length and breadth. So students should know that the width is also a breadth. So, the formula will be the same as is given for the perimeter of a rectangular. Students should also know that the distance will be the product of 4 and the perimeter of the field.