English

The Length of a Rectangle Exceeds Its Breadth by 9 Cm. If Length and Breadth Are Each Increased by 3 Cm, the Area of the New Rectangle Will Be 84 Cm2 More than that of the Given Rectangle. - Mathematics

Advertisements
Advertisements

Question

The length of a rectangle exceeds its breadth by 9 cm. If length and breadth are each increased by 3 cm, the area of the new rectangle will be 84 cm2 more than that of the given rectangle. Find the length and breath of the given rectangle.

Numerical

Solution

Let the breadth of the rectangle be x cm . 
Therefore, the length of the rectangle will be (x + 9) cm. 
∴ Area of the rectangle =\[ x(x + 9) {cm}^2. \] 
If the length and breadth are increased by 3 cm each, 
area \[= (x + 3)(x + 9 + 3) {cm}^2. \]
Now, 
\[(x + 3)(x + 12) - x(x + 9) = 84\]
or \[x^2 + 15x + 36 - x^2 - 9x = 84\]
or 6x = 84 - 36
or \[x = \frac{48}{6} = 8 . \]
Thus, breadth of the rectangle = 8 cm. 
Length of the rectangle = (8 + 9) = 17 cm.

shaalaa.com
  Is there an error in this question or solution?
Chapter 9: Linear Equation in One Variable - Exercise 9.4 [Page 30]

APPEARS IN

RD Sharma Mathematics [English] Class 8
Chapter 9 Linear Equation in One Variable
Exercise 9.4 | Q 25 | Page 30

Video TutorialsVIEW ALL [1]

Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×