Concept:Understanding the relationship between the perimeter, length, and breadth of a rectangle.
Explanation:Let's denote the breadth of the rectangle as
b cm and the length as
l cm.
We are given two pieces of information:
1. The length is 3 cm more than its breadth:
l=b+3. This can also be written as
l−b=3.
2. The perimeter of the rectangle is 30 cm.
The formula for the perimeter of a rectangle is
P=2×(l+b).
Substituting the given perimeter, we get
30=2×(l+b).
Dividing both sides by 2, we find
l+b=15.
Now we have a system of two linear equations:
Equation (1):
l+b=15Equation (2):
l−b=3To find the length (
l), we can add Equation (1) and Equation (2):
(l+b)+(l−b)=15+32l=18Divide by 2 to get the length:
l=218​=9 cm.
We can also find the breadth by substituting
l=9 into Equation (1):
9+b=15, which gives
b=15−9=6 cm.
The question asks for the length of the rectangle.
Answer:9 cm