Asquare has a perimeter of 28 feet. < br />
what is its area?

You know that a square has four even sides, and that the perimeter of a shape is l+w+l+w, where l means length and w means width.
The perimeter of a square can also just be 4 times any of the side lengths, as they're all the same. From this reasoning, you can find the length of any/all sides by dividing the perimeter by 4. 
28/4=7, so the side length of the square would be 7 feet.
Area is equal to length times width. And in the case of a square, the area would be length-squared.
7x7=49
The area of a square with a perimeter of 28 feet is 49 feet. Hope this helps :-)

Side multiply side =. Your answer whatch is 49 your perimeter is7 +7+7+7= 28 so u are right

1. 0.3 •4 is the same as 4 groups of 0.32. 7•0.8 is the same as 7 groups of 0.83. it increases by 0.5 every time, so 0.5x4 it increases by 0.9 every time, so 0.9x5. 0.9•12=10.86. 0.47•5=2.35i can finish the next ones in a separate post