Find the perimeter and area of the rectangle if it is 40 mm wide and 12 cm long

For convenience, we will convert all values to one unit of measurement – millimeters. 1 cm – 10 mm.
Then we get:
Width – 40 mm (on condition).
Length – 12 cm (on condition) = 120 mm.
The perimeter is the sum of all sides. Since the rectangle has two equal lengths and two equal widths, we get:
P = 40 + 40 + 120 + 120 = 320 mm.
Area is the product of the length and width of a shape, in this case a rectangle. That is, you need to multiply its length (40 mm) and its width (120 mm).
S = 40 * 120 = 4800 mm².
Answer: 320 mm – perimeter; 4800 mm² – area.