What are the sides of a rectangle if its area is 12 cm and the perimeter is 26 cm?
May 6, 2021 | education
| 1. Let’s denote the lengths of the sides of the rectangle by X and Y.
2. Using the formula for finding the area of a rectangle, we write the expression:
X * Y = 12
3. Using the formula for finding the perimeter of a rectangle, we write the expression:
2 * (X + Y) = 26.
4. Find X and Y. Let us express Y through X from the perimeter formula:
X + Y = 13;
Y = 13 – X.
5. Substitute in the area formula Y, expressed through X, and solve:
X * (13 – X) = 12;
13X – X ^ 2 – 12 = 0;
X ^ 2 – 13X + 12 = 0;
D = 13 ^ 2 – 4 * 12 = 121;
X1 = (13 + √121) / 2 = 12;
X2 = (13 – √121) / 2 = 1;
Y1 = 13 – 12 = 1;
Y2 = 13 – 1 = 12.
Answer: the sides of the rectangle are 12 cm and 1 cm.
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