The length of rectangle is thrice ti Breadth. If the length is decrease 9 and breadth is increase 9. If the area Increase 81 sq cm. Then what is length
Answers
Assumption
Let the breadth be p
Also,
Length be 3p
Length is decreased by 9cm
= 3p - 9 cm
Also,
Breadth = p + 9 cm
Here we have to apply,
Area of rectangle = Lenght × Breadth
(3p - 9)(p + 9) - 3p × p = 81
3p² + 27p - 9p - 81 - 3p² = 81
18p - 81 = 81
18p = 162
p = 162/18
p = 9 cm
Hence,
Breadth = 9 cm
Length = 3p
= 3 × 9
= 27 cm
Question :
The length of rectangle is thrice of its Breadth. If the length is decrease 9cm and breadth is increase 9cm . If the area Increase 81 sq cm. Then what is length ?
Solution :
Let the Breadth of rectangle be x .
⇒Length of rectangle be 3 x
Diagram :.
According to the question:
If the length is decrease 9cm and breadth is increase 9cm. Then the area Increase is 81 sq cm.
⇒ length ,l' = 3x-9
and breadth , b' = x+9
We know that ,
area of a rectangle = length × breadth
⇒Increase in Area = 81 sq cm
Therefore,
Breadth ,x = 9 cm
and Length = 3x= 3× 9= 27 cm