Question

find the perimeter of a rectangle whose length is 5a + 6b and breadth is 4a - b​

Answer 1

P=2(l+w)

l Length

5

w Width

Enter value

Answer 2

Answer :

Given :

The length of a rectangle is 5a + 6b

It's breadth is 4a - b

To find :

It's perimeter

Formula used :

2 × ( l + b )

Where l stands for length and b for breadth

Solution :

$\sf{\implies\: Perimeter\:=\:2\:\times\:(\:l\:+\:b\:)}$

$\sf{\implies\: Perimeter\:=\:2\:\times\:(\:5a\:+\:6b\:+\:4a\:-\:b\:)}$

$\sf{\implies\: Perimeter\:=\:2\:\times\:(\:5a\:+\:4a\:6b\:-\:b\:)}$

$\sf{\implies\: Perimeter\:=\:2\:\times\:(\:9a\:+\:5b\:)}$

$\sf{\implies\: Perimeter\:=\:18a\:+\:10b}$

Step by step calculation :

We know that the formula for finding the perimeter of a rectangle is 2 × ( l + b ) .

Now , as given in the Question itself The length of a rectangle is 5a + 6b

It's breadth is 4a - b

We have to find the perimeter

So , substituting the values of length and breadth in the formula of perimeter

We will get ,

$\sf{\implies\: Perimeter\:=\:2\:\times\:(\:5a\:+\:6b\:+\:4a\:-\:b\:)}$

Now on taking the like terms together we get ,

$\sf{\implies\: Perimeter\:=\:2\:\times\:(\:5a\:+\:4a\:6b\:-\:b\:)}$

Adding on 5a + 4a = 9a and subtracting b from 6b = 5b

Further multiplying the terms with two

We get , perimeter = 18a + 10b