Question

if the perimeter of a rectangle is 26cm and it's breadth is 4cm it's length is now going to be what

Answer 1

The perimeter of the rectangle is given as;

$P=26\operatorname{cm}$

the breadth is also given as;

$b\text{ = 4cm}$

Recall that the formula for the perimeter of a restangle is;

$P=\text{ 2(l+b) = 2l + 2b}$

where,

l is the length and b is the breadth

So, let us substitute the values of P and b into the formula;

$\begin{gathered} P=2l+2b \\ 26=2l+2(4) \\ 26=2l+8 \end{gathered}$

Now, let us solve for l;

$\begin{gathered} 26=2l+8 \\ \text{subtract 8 from both sides.} \\ 26-8=2l+8-8 \\ 18=2l \\ \text{divide both side by 2;} \\ \frac{2l}{2}=\frac{18}{2} \\ l=9\text{ cm} \end{gathered}$

Therefore the length of the of the rectangle is 9cm