One side of the rectangle is 7 cm larger than the other, and its perimeter = 70 cm. What is its area?

| June 15, 2021 | education

According to the condition of the task, it is necessary to find the area of ​​the rectangle, which is calculated by the formula:

S = a * b.

We do not know its sides, we only know that the length is 7 cm greater than the width, and the perimeter = 70 cm.

The sum of all sides of such a figure is calculated by the formula:

P = 2a + 2b. Substitute the known values ​​and write the equation to find the sides:

2 * (x + 7) + 2x = 70. Let’s open the brackets:

2x + 14 + 2x = 70. Let’s perform actions with the coefficients of the variable on the left side of the equation, and transfer the number to the right, while the sign in front of it changes to the opposite.

4x = 70 – 14 = 56.

x = 56: 4 = 14 cm.

Therefore, width = 14 cm and length = 14 + 7 = 21 cm.

Let’s calculate the area:

S = 14 * 21 = 294 cm².



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