# The length of the rectangle is 16 cm, the width is 4 times less. Calculate the area of the rectangle.

**The length of the rectangle is 16 cm, the width is 4 times less. Calculate the area of the rectangle. The area of the hall is 135 m2, the length is 15 m. Calculate the width of the hall. The area of the rectangular plot is 216 m2, its length is 18 m. Calculate the perimeter. Calculate the volume of a cube with a side of 17 mm.**

Let be:

S is the area of the rectangle;

a is the length of the rectangle;

b is the width of the rectangle;

S = a * b.

1) a = 16 cm, b – 4 times less than the length of the rectangle.

Find the area of the rectangle.

b = 16/4 = 4 cm;

S = a * b = 16 cm * 4 cm = 16 * 4 cm² = (10 * 4 + 6 * 4) cm² = (40 + 24) cm² = 64 cm².

2) S = 135 m², a = 15 m.

S = a * b;

b = S / a = 135 m² / 15 m = 135/15 m = 45/15 m + 45/15 m + 45/15 m = 3 m + 3 m + 3 m = 9 m.

3) S = 216 m², a = 18 m.

Let’s find the perimeter.

b = S / a = 216 m² / 18 m = 216/18 m = 12 m.

P = 2 * (a + b) = 2 * (18 m + 12 m) = 2 * 30 m = 60 m.

4) Calculate the volume of a cube with a side of 17 mm.

V = (17 mm) ^ 3 = 4913 mm ^ 3.