Answer:
900 cm²
Explanation:
Perimeter of a rectangle is given by
P=2(l+w)
Where l and w are length and width respectively.
Substituting P with 120 cm
120=2(l+w)
Divide both sides by 2
60=l+w
Making w the subject of formula
w=60-l
Area, A=lw
Substitute w with 60-l
A=l(60-l)=60l-l²
Since A=60l-l²
Get the first derivative of A with respect to l
0=60-2l
l=60/2=30
Therefore, w=60-l=60-30=30
The length abd width are both 30cm. This is a square and a square is also a type of rectangle since it has four sides.
Area=30*30=900cm²