The perimeter of a square is four times its sidelength, so a square with perimeter 64 inches has sides with length 16 inches. Use the area formula:

\(\displaystyle A = s^{2} = 16^{2} = 256\)

A square that has an area of 81 has sides that are the square root of 81 (side² = area for a square).  Thus each of the four sides is 9.  The sum of three of these sides is \(\displaystyle 9 + 9 + 9 = 27\).

A cube comprises six faces, each of which is a square. To find its total surface area, find the area of one face by squaring its sidelength:

\(\displaystyle 3 \frac{1}{2} \times 3 \frac{1}{2} = \frac{7}{2} \times \frac{7}{2} = \frac{49}{4} \textrm{ in}^{2}\)

Then multiply this by six:

\(\displaystyle 6 \times \frac{49}{4} =\frac{6}{1} \times \frac{49}{4} = \frac{3}{1} \times \frac{49}{2} = \frac{147}{2} = 73 \frac{1}{2} \textrm{ in}^{2}\)

A cube comprises six faces, each of which is a square. To find its total surface area, find the area of one face by squaring its sidelength:

\(\displaystyle 2.6 \times 2.6 = 6.76 \textrm{ cm}^{2}\)

Then multiply this by six:

\(\displaystyle 6 \times 6.76 = 40.56 \textrm{ cm}^{2}\)

A cube comprises six faces, each of which is a square. To find its total surface area, find the area of one face by squaring its sidelength:

\(\displaystyle 25 \times 25 = 625 \textrm{ in}^{2}\)

Then multiply this by six:

\(\displaystyle 6 \times 625 = 3,750\textrm{ in}^{2}\)

A cube comprises six faces, each of which is a square. To find its total surface area, find the area of one face by squaring its sidelength:

\(\displaystyle 12 \times 12 = 144 \textrm{ cm}^{2}\)

Then multiply this by six:

\(\displaystyle 6 \times 144 = 864\textrm{ cm}^{2}\)

Each side can be divided into three 3-foot sections.  This gives a total of \(\displaystyle 3\times3=9\) squares.  Another way of looking at the problem is that the total area of the large square is 81 and each smaller square has an area of 9.  Dividing 81 by 9 gives the correct answer.

Figure A has area \(\displaystyle 3 ^{2} = 3 \times 3 = 9\) square feet.

Figure B has dimensions \(\displaystyle 30 \div12 = 2 \frac{1}{2}\) feet by \(\displaystyle 42 \div12 = 3 \frac{1}{2}\) feet, so its area is 

\(\displaystyle 2 \frac{1}{2} \times 3 \frac{1}{2} = \frac{5}{2} \times \frac{7}{2} = \frac{35}{4} = 8 \frac{3}{4}\) square feet.

Figure C has area \(\displaystyle 2 \times 4 = 8\) square feet.

From least area to greatest, the figures rank C, B, A.

The area of any quadrilateral is found by multiplying the length by the width. Because a square has four equal sides, the length and width are the same. For the square in this question, the length and width are \(\displaystyle 11\: cm\).

Remember: area is always given in units² .

The area of a square is found by multiplying the length of a side by itself.

\(\displaystyle A=s\times s=s^2\)

If one side is 3 yards, this means one side is 9 feet since there are 3 feet in a yard.

\(\displaystyle 3\ \text{yards}\times3\ \text{feet per yard}=9\ \text{feet}\)

Since every side is of equal length, you would multiply 9 feet by 9 feet to find the area.

\(\displaystyle A=s\times s\)

\(\displaystyle s=9\)

\(\displaystyle A=9\times9=81\)

This results in 81 square feet, which is the correct answer.