The perimeter of a square is represented by (12x) cm. The side length can be represented as (x + 5) cm. What is the length of a side of the square?
2006-11-17 03:50:59 · 6 answers · asked by ♥ kellycakes ♥ 1 in Science & Mathematics ➔ Mathematics
4(x+5)=12x
4x+20=12x
adding -4x
20=8x
dividing by 8
x=2.5cm
2006-11-17 03:53:25 · answer #1 · answered by raj 7 · 0⤊ 0⤋
All the sides of a square are the same length, so the perimeter is 4 * the side length. In this case, that means that 12x = 4(x + 5). Multiply out the parentheses: 12x = 4x + 20. Subtract 4x from each side: 8x = 20. Divide by 8: x = 2.5.
Now, check your answer: 2.5 + 5 is 7.5, 7.5 * 4 is 30, and 2.5 * 12 is 30. It works.
Therefore x = 2.5, and the length is 5 + x or 7.5.
2006-11-17 03:55:00 · answer #2 · answered by Amy F 5 · 1⤊ 0⤋
let
4 = four sides of the square
x + 5 = one side of the square
12x = the perimeter
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The equation
4(x + 5) = 12x
4x + 20 = 12x
4x + 20 - 4x = 12x - 4x
20 = 8x
20 / 8 = 8x/8
2 4/8 = x
2 1/2 = x
2.5 = x
The answer is x = 2.5 cm
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The length of a side of the square
x + 5
2.5 + 5 = 7.5 cm
The length of a side of the square is 7 . 5 cm
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2006-11-17 04:42:51 · answer #3 · answered by SAMUEL D 7 · 1⤊ 0⤋
P=4(sides) for a square
So
4*(x+5)=12x
4x+20=12x
-4x -4x
20=8x
x=2.5
each side then equals (2.5+5)
or 7.5
2006-11-17 04:29:58 · answer #4 · answered by math_teacher_02 2 · 0⤊ 0⤋
OK, this is what I think the answer is:
(12x) cm = 1 square
12x/2 = 1/2
6x = 0.5, or 1/2 of the square
6x/2 = 0.5/2
3x = 0.25, or 1/4 of the square.
Each side leingth is (3x) cm.
2006-11-17 03:57:05 · answer #5 · answered by Haveee FUN YAY! 1 · 0⤊ 1⤋
2.5cm
4 ( x + 5 ) = 12x
4x + 20 = 12x
4x - 12x = -20
- 8x = -20
x = 20/8
x = 2.5
2006-11-17 03:57:40 · answer #6 · answered by Anonymous · 0⤊ 0⤋