A wire whose length is at most 62 cm is bent to form a rectangle. If the length of rectangle is 7 cm longer than the width, what is tje maximum area of rectangle?

Sagot :

62/2=31
x is one side of the rectangle
x+7 another side
x+x+7=31
2x+7=31
2x=31-7
2x=24
x=12
12+7=19
12 and 19 are the sides of the rectangle
12x19=228cm^2
Width: x
Lenght: x + 7
Perimeter of the rectangle: 62 cm

Perimeter = 2 (Width) + 2 (Length)
62 = 2 (x) + 2 (x+7)
62 = 2x + 2x + 14
62 - 14 = 4x
48 = 4x

4x/4 = 48/4
x = 12 

Substitute 12 for x in dimensions:
Width; x = 12 cm
Length: 12 + 7 = 19 cm

Length × Width = Area
(19 cm) (12 cm) = 228 cm²

The maximum area of the rectangle is 228 cm².