The width of a rectangular garden is 9 feet, and its length is 12 feet. Three of these expressions equal the perimeter of the garden, in feet. Which expression does NOT?
9 + 12
2 • 9 + 2 • 12
9 + 12 + 9 + 12
2(9 + 12)
The width of a rectangular garden is 9 feet, and its length is 12 feet. Three of these expressions equal the perimeter of the garden, in feet. Which expression does NOT?
Share
The expression that does NOT equal the perimeter of the garden is 9 + 12.
Here’s why:
1. The perimeter ( P ) of a rectangle is calculated using the formula:
[
P = 2 cdot text{length} + 2 cdot text{width}
]
For this garden, the width is 9 feet and the length is 12 feet.
2. Now let’s evaluate each expression:
– 9 + 12 = ( 21 ) feet (this only adds the length and width, not the full perimeter)
– 2 • 9 + 2 • 12 = ( 18 + 24 = 42 ) feet (correct perimeter calculation)
– 9 + 12 + 9 + 12 = ( 21 + 21 = 42 ) feet (this sums all four sides, which is correct)
– 2(9 + 12) = ( 2 times 21 = 42 ) feet (this also calculates the perimeter correctly)
In conclusion, the expression 9 + 12 does NOT give the correct perimeter of the garden. Keep up the great work in understanding these concepts! If you have more questions, feel free to ask.