Find the area of a rectangle whose length is 4cm and the perimeter is 14cm

Let’s remember what the perimeter of a rectangle is – it is the sum of the lengths of all its sides. Let’s write the formula:

P = a + a + b + b = 2a + 2b cm.

Since we know the perimeter of a given rectangle, as well as the length of one of its sides, therefore, we can calculate what the length of its other side is equal to. Find out the length of the second side if the perimeter is 14 cm, and the known side is 4 cm.

14 = 2 * 4 + 2 * b;

2 * b = 14 – 2 * 4;

2 * b = 14 – 8;

2 * b = 6;

b = 6/2;

b = 3 cm.

Let’s calculate the area of the rectangle:

S = 4 * 3 = 12 cm ^ 2.

Answer: The area of the rectangle is 12 cm ^ 2.