Respuesta :

Knowledgestorm
The area of a rectangle is found by multiplying the length by the width. 
ie A = l x w 
given that the area is 40 square cm and one side is 8cm (I'll assume that it is the length) the formula becomes 
40 = 8 x w
Divide each side by 8 then 

40/8 = (8 x w)/8
5 = w
So the width must be 5 cm.
Perimeter = 2 x (l + w)
=2 x (8 + 5)
=2 x 13
=26 cm
dahamivherath
formula of area of a rectangle is length ×width 

in this question area equals 40cm and width is 8cm, so to find the length of the rectangle you have to divide 40 by 8,
40÷8=5

answer= 5cm
hope i helped.