Question

Area of rectangle $=72c{{m}^{2}}$ and its breadth $=8cm$. What is the length of a rectangle?

Answer 1

Hint: Type of question is based on finding the unknown dimension of figures. As in our question we had to find out the length of the rectangle. So we will simply put the formula of the area of the rectangle. Since in this formula area of rectangle is given, breadth of rectangle is also given, we have only one variable i.e. length of rectangle, so by simplifying the equation, we will get the rectangle.


Complete step by step solution:
Moving ahead in step-by-step method with question, we had given;
Area of rectangle$=72c{{m}^{2}}$
Breadth of rectangle$=8cm$
Length of rectangle $=?$
We had to find out the rectangle;
So as we know that area of rectangle is length multiplied by breadth i.e.
Area of rectangle$=length\times breadth$
As we know that, Area of rectangle $=72c{{m}^{2}}$and breadth of rectangle$=8cm$ and length is unknown which we need to find out, so replace the value in the above expression; from where we will get;
\[\begin{align}
  & Area\text{ }of\text{ }rectangle=length\times breadth \\
 & 72c{{m}^{2}}=(length)\times 8cm \\
\end{align}\]
Now bring $8cm$ to right side (as it is in multiplication in left side so it will come in division in right side), which on solving it we will get;
\[\dfrac{72c{{m}^{2}}}{8cm}=(length)\]
As we know that 72 is 9 times of 8, so we can write it further as;
\[\begin{align}
  & \dfrac{72c{{m}^{2}}}{8cm}=(length) \\
 & 9cm=length \\
\end{align}\]
So from here we can say that the length of the rectangle is $9cm$.
Hence answer is $9cm$.

Note: To solve the type of question you must remember some basic formula of finding the area of figures. Moreover you can directly put the formula of the given condition to find the unknown value, as in our case area of rectangle is given so we had put the formula to area of rectangle.