Areas of Polygons for 7th Grade - Examples, Exercises and Solutions

This question is a bit confusing. We need start by identifying which parts of the data are relevant to us.

Remember the formula for the area of a triangle:

The height is a straight line that comes out of an angle and forms a right angle with the opposite side.

In the drawing we have a height of 6.

It goes down to the opposite side whose length is 5.

And therefore, these are the data points that we will use.

We replace in the formula:

$\frac{6\times5}{2}=\frac{30}{2}=15$

First, we will identify the data points we need to be able to find the area of the triangle.

the formula for the area of the triangle: height*opposite side / 2

Since it is a right triangle, we know that the straight sides are actually also the heights between each other, that is, the side that measures 5 and the side that measures 7.

We multiply the legs and divide by 2

$\frac{5\times7}{2}=\frac{35}{2}=17.5$

In this particular problem, despite being given certain measurements, the diagram lacks sufficient clarity to identify which corresponds definitively as the base and which as the perpendicular height of the parallelogram. This insufficiency means that without further context or labeling to avoid assumptions that may lead to error, it is not feasible to calculate the area confidently using the standard formula.

Thus, the answer to the problem is that it is not possible to calculate the area with the provided data.

To solve this problem, let's apply the formula for the area of a parallelogram:

The formula for the area of a parallelogram is $\text{Area} = \text{base} \times \text{height}$.

Here, the base of the parallelogram is 6 cm, and the height is 4.5 cm.

Substituting these values into the formula gives:

$\text{Area} = 6 \times 4.5$

Performing the multiplication:

$\text{Area} = 27$ square centimeters.

Therefore, the area of the parallelogram is $27 \, \text{cm}^2$.

Referring to the given multiple-choice answers, the correct choice is:

Choice 3: $27$.

To solve this problem, we'll follow these steps:

• Step 1: Identify the given information
• Step 2: Apply the appropriate formula
• Step 3: Perform the necessary calculations

Now, let's work through each step:
Step 1: The problem provides us with a base ($b$) of 7 units and a height ($h$) of 5 units, perpendicular to this base.
Step 2: We'll apply the formula for the area of a parallelogram, which is $\text{Area} = b \times h$.
Step 3: Substituting the given values, $\text{Area} = 7 \times 5 = 35$.

Therefore, the area of the parallelogram is $35$ square units.

To solve this problem, we'll follow these steps:

• Step 1: Identify the base and height from the information provided.
• Step 2: Apply the formula for the area of a parallelogram.
• Step 3: Calculate the area by multiplying the base and height.

Now, let's work through each step:
Step 1: The base of the parallelogram is given as $8$ units, and the height is given as $5$ units.
Step 2: We use the formula for the area of a parallelogram: $\text{Area} = \text{base} \times \text{height}$.
Step 3: Plugging in the given values, we calculate the area as follows:
$\text{Area} = 8 \times 5 = 40$.

Therefore, the area of the parallelogram is $40$ square units, which corresponds to choice 2.

To solve this problem, we must calculate the area of the given parallelogram using the formula:

$\text{Area} = \text{base} \times \text{height}$

Assuming the figure (as described) provides a base of $9$ units and a height of $4$ units, we substitute these values into the formula:

$\text{Area} = 9 \times 4 = 36 \text{ square units}$

The necessary calculations have been carried out using the correct dimensions, ensuring dimensional consistency and precise arithmetical methods. Therefore, the calculated area of the parallelogram is $36$.

Given the multiple-choice options, the correct choice is the one specifying the area as $36$, confirming the answer provided in choice 3.

From the given constraints, it is impossible to confidently compute the area of the parallelogram because of insufficient and unclear relationships between provided figures and the calculations they must produce. Clarity on which numbers correspond to the height and base—as or any definitional angles—is absent.

The correct answer, aligning with acknowledged drawing limitations, is: It is not possible to calculate.

The triangle we are looking at is the large triangle - ABC

The triangle is formed by three sides AB, BC, and CA.

Now let's remember what we need for the calculation of a triangular area:

(side x the height that descends from the side)/2

Therefore, the first thing we must find is a suitable height and side.

We are given the side AC, but there is no descending height, so it is not useful to us.

The side AB is not given,

And so we are left with the side BC, which is given.

From the side BC descends the height AD (the two form a 90-degree angle).

It can be argued that BC is also a height, but if we delve deeper it seems that CD can be a height in the triangle ADC,

and BD is a height in the triangle ADB (both are the sides of a right triangle, therefore they are the height and the side).

As we do not know if the triangle is isosceles or not, it is also not possible to know if CD=DB, or what their ratio is, and this theory fails.

Let's remember again the formula for triangular area and replace the data we have in the formula:

(side* the height that descends from the side)/2

Now we replace the existing data in this formula:

$\frac{CB\times AD}{2}$

$\frac{11.6\times3}{2}$

$\frac{34.8}{2}=17.4$

To calculate the area of the rectangle, we multiply the length by the width:

$15\times3=45$

To solve this problem, we'll follow these steps:

• Step 1: Identify the given information
• Step 2: Apply the appropriate formula
• Step 3: Perform the necessary calculations

Now, let's work through each step:

Step 1: The problem gives us the width, $W = 18$ cm, and the length, $L = 2$ cm.

Step 2: We'll use the formula for the area of a rectangle: $\text{Area} = \text{Length} \times \text{Width}$

Step 3: Plugging in the values, we get: $\text{Area} = 2 \times 18 = 36 \text{ square centimeters}$

Therefore, the area of the rectangle is $36$ square centimeters.

In the provided answer choices, the correct choice is:

Choice 3: $36$

We use the formula (base+base) multiplied by the height and divided by 2.

Note that we are only provided with one base and it is not possible to determine the size of the other base.

Therefore, the area cannot be calculated.

To find the area of the trapezoid, we would ideally use the formula:

$A = \frac{1}{2} \times (b_1 + b_2) \times h$

where $b_1$ and $b_2$ are the lengths of the two parallel sides and $h$ is the height. However, the given information is incomplete for these purposes.

The numbers provided ($6$, $7$, $12$, and $5$) do not clearly designate which are the bases and what is the height. Without this information, the dimensions cannot be definitively identified, making it impossible to calculate the area accurately.

Thus, the problem, based on the given diagram and information, cannot be solved for the area of the trapezoid.

Therefore, the correct answer is: It cannot be calculated.

To solve this problem, we'll calculate the area of the trapezoid using the standard formula:

• Step 1: Identify the given dimensions:
• Shorter base $b_1 = 5$.
• Longer base $b_2 = 8$.
• Height $h = 3$.

Step 2: We apply the trapezoid area formula, which is:

$A = \frac{1}{2} \times (b_1 + b_2) \times h$.

Step 3: Substitute the given values into the formula:

$A = \frac{1}{2} \times (5 + 8) \times 3$.

Step 4: Perform the calculations:

$A = \frac{1}{2} \times 13 \times 3$.

$A = \frac{1}{2} \times 39$.

$A = 19.5$ or $19 \frac{1}{2}$.

The area of the trapezoid is $19 \frac{1}{2}$.

To solve this problem, we'll follow these steps:

• Identify the given measurements: the lengths of the parallel sides (bases) and the height.
• Use the trapezoid area formula to calculate the area.
• Perform the necessary arithmetic to find the numerical answer.

Now, let's work through each step:
Step 1: The given measurements are $\text{Base}_1 = 9$, $\text{Base}_2 = 12$, and the height = 5.
Step 2: The formula for the area of a trapezoid is $\text{Area} = \frac{1}{2} \times (\text{Base}_1 + \text{Base}_2) \times \text{Height}$.
Step 3: Substituting the numbers into the formula, we have:
$\text{Area} = \frac{1}{2} \times (9 + 12) \times 5$

Calculating inside the parentheses first:
$9 + 12 = 21$

Then multiply by the height:
$21 \times 5 = 105$

Finally, multiply by one-half:
$\frac{1}{2} \times 105 = 52.5$

Therefore, the area of trapezoid $ABCD$ is $52.5$ .