The rectangle is 21 cm long and 2/7 wide. What is the area of the rectangle?

To find the area, we use the formula known for a rectangle: S = a * b. We know the length, a = 21 cm. We will calculate the width b. From the conditions of the assignment, you can write:

b = 2/7 * a
b = 2/7 * 21 = 2 * 3 = 6 cm

Now we can easily calculate the area:

S = 21 * 6 = 126 cm²

Answer: 126 cm².

One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.