The perimeter of the rectangle is 22 cm, and its area is 30 cm². find the sides of the rectangle.
April 29, 2021 | education
| 1. Let one side of the rectangle be x, then the other is y.
2.The perimeter is equal to the sum of all sides, since 2 sides are the same, the equation will look like:
2x + 2y = 22.
3. The area of a rectangle is equal to the product of its sides, the equation will look like:
x * y = 30.
4. Let’s solve the system of equations. From the first equation, we express x:
x = (22 – 2y): 2;
x = 11 – y.
5. Substitute the value of x in the second equation:
(11 – y) * y = 30;
11y – y ^ 2 = 30;
-y ^ 2 + 11y – 30 = 0.
Let’s find the discriminant:
D = b ^ 2 -4ac = 121 – 120 = 1.
D> 0, the equation has 2 roots:
x1 = (-11 + 1) / (-2) = 5;
x2 = (-11 – 1) / (-2) = 6.
Answer: One side of the rectangle is 5 cm, the other side is 6 cm.
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