The length of a rectangle is three meter more than its width. If both length and breadth are decreased by 2 centimeter, then the area is reduced by 18 square units. Find the dimensions of the rectangle. Then I will follow and mark as branliest
Answers
Answer:
Length of Rectangle be (X + 3)m
Width of Rectangle be X
Area of Rectangle = L×B
=(X+3) × X m^2
New Area
1m = 100cm
1cm = (1 /100) m
2cm = (1 / 100) × 2 = 0.02 m
(X+3)-0.02 × (X - 0.02) = 18
(0.02X + 0.06) (X - 0.02) = 18
0.02X^2 + 0.02X × 0.02 + 0.06 × X - 0.06× 0.02 = 18
0.02X^2 + 0.0004X + 0.0036X - 0.0012 = 18
0.02X^2 + 0.0040X - 0.0012 - 18 = 0
0.02X^2 + 0.0040X - 0.0030 = 0
Divided whole thing by 0.02
X^2 + 0.2X - 0.15 = 0
X^2 + 0.5X - 0.3X - 0.15 = 0
X ( X + 0.5 ) - 0.3 ( X + 0.5 ) = 0
(X - 0.3) ( X + 0.5 ) = 0
X = 0.3 meter
Therefore
Dimensions of Rectangle
Lenght = X + 3 = 0.3 + 3 = 3.3 meter
Width = X = 0.3 meter
●GIVEN :
- LENGTH OF A RECTANGLE IS 3 METER MORE THAN ITS WIDTH
- IF BOTH LENGTH AND BREADTH ARE DECREASED BY TWO METER THEN AREA IS REDUCED BY 18 sq.units
●TO FIND :
- DIMENSIONS OF RECTANGLE
●SOLUTION :
○CASE - I :
LET THE WIDTH OF RECTANGLE BE X cm
THEN LENGTH = X + 3 cm
AREA OF RECTANGLE = L × B = X ( X + 3) = X^2 + 3X sq.cm
○CASE - II :
LENGTH = X + 3 - 2 = X + 1 cm
BREADTH = X - 2 cm
AREA = X^2 + 3X - 18 sq.cm
=> L × B = X^2 + 3X - 18
=> (X + 1 )( X - 2) = X^2 + 3X - 18
=> X^2 - 2X + X - 2 = X^2 + 3X - 18
=> -2 - X = 3X - 18
=> 0 = 4X - 16
=> 4X = 16 => X = 4
THEN ,
BREADTH = (X) = 4 cm
LENGTH = ( X + 3) = 7 cm
∴ THE DIMENSIONS OF THE RECTANGLE ARE 4 cm & 7cm