Question

............ is expressed in square units.
A. Perimeter
B. Area
C. Square
D. Rectangle

Answer 1

Hint: Since the question has asked what option is expressed in square units, we will just go option by option first we will find the perimeter of any shape and see the unit of perimeter and then we will do the same for the area of a polygon. As for options C and D , there is nothing to measure. We will just write that these are only types of polygons.

Complete step-by-step answer:
Let us start by checking each option,
First we have the perimeter of a figure: Now, we know that perimeter is defined as the length of the outline of a shape. If we want to find out the perimeter of a rectangle or square or any other polygon all you have to do is add all the sides and get the perimeter of that shape. You measure perimeter in linear units, which is one dimensional. Examples of units of measure for length are inches, centimeters, or feet. For example, let’s take the following figure :

Now we will calculate the perimeter of this figure:
$\begin{align}
  & P=AB+BC+CD+DE+EA \\
 & P=15+10+5+9+20=49\text{ m } \\
\end{align}$
So, we see that the unit of perimeter is the unit of length that is meters.
Next, we have area: Now, we define the area of a two-dimensional figure as the amount of surface the shape covers. You measure area in square units of a fixed size. Examples of square units of measure are square inches, square centimeters, or square miles. However, there are different formulas for finding out the area of different shapes. For example let’s take a square of side $4\text{ m}$ , area of this square will be (side $\times $ side) that is $16\text{ }{{\text{m}}^{2}}$ .
You can also count how many squares of a certain size will cover the region inside the polygon.
For example, let’s take a example of$4\times 4$ square:

You can count there are 16 squares, so the area is 16 squares units.
Next options are square and rectangle, since these are different types of polygons there is no way to measure them. They are just two dimensional shapes.
Since we found out that the area is expressed in square units.

So, the correct answer is “Option B”.

Note: Square units are often confused with Unit squares. A unit square with sides measuring 1 unit while square units is a unit of measurement. When finding the area if there is a larger square or the units are smaller, it could take a long time to count therefore we will use the formula for finding out the area some of the examples are as follows:
Area of a triangle: $\dfrac{1}{2}\times b\times h$ , where $b$ is the base and $h$ is the height of the triangle.
Area of a square: ${{a}^{2}}$ , where $a$ is the side of the square.
Area of a rectangle: $l\times b$ , where $l$ is the length and $b$ is the breadth of the rectangle.