Step-by-step explanation:
you understand the words "perimeter" and "area" ?
I am asking, because once you know what these words mean, this is a very simple task to do.
therefore, I have to assume you don't understand these concepts yet, and I need to give you some explanation with the solution.
"perimeter" means the circumference, the way or distance you need to walk or drive to get fully around the object one time.
look at the picture. you see that such a rectangle has two longer and two shorter sides. the longer sides (lengths) are equally long. and the shorter sides (widths) are equally long.
now, how many yards is it to go one time around this rectangle ?
it is
7 + 3 + 7 + 3 = 20 yards
this is the case with all rectangles, which is why the general formula for the perimeter of a rectangle is
p = 2×length + 2×width
"area" means how much ground is covered by this shape or object ?
we measure this in general in square units. little squares that fill the whole object or shape, and we count (or then calculate) how many there are.
for such an object, where the sides are meshed in yards, it makes most sense to use square yards (yards²) as measurement unit. a square yard is a square, where each side is 1 yard long.
how many are there ?
we can place a first row of 7 such square yards along the length of 7 yards.
how many rows of square yards can I place ?
well, exactly as many the size of the width in yards (3).
so, 3 rows of 7 square yards, that are how many square yards in total ?
aha !
yes, 7×3 = 21 yards² or short 21 yd²
