An equilateral triangle has an apothem measuring 2.16 cm and a perimeter of 22.45 cm.

What is the area of the equilateral triangle, rounded to the nearest tenth?

A. 2.7 cm²
B. 4.1 cm²
C. 16.2 cm²
D. 24.2 cm²



Answer :

To find the area of an equilateral triangle using its apothem and perimeter, we can use the formula for the area of a regular polygon:

[tex]\[ \text{Area} = \frac{1}{2} \times \text{Perimeter} \times \text{Apothem} \][/tex]

Given:
- Apothem ([tex]\(a\)[/tex]) = 2.16 cm
- Perimeter ([tex]\(P\)[/tex]) = 22.45 cm

First, we plug these values into the formula:

[tex]\[ \text{Area} = \frac{1}{2} \times 22.45 \, \text{cm} \times 2.16 \, \text{cm} \][/tex]

Next, we calculate the product of the perimeter and the apothem:

[tex]\[ 22.45 \times 2.16 = 48.092 \][/tex]

Now, we divide this product by 2 to find the area of the triangle:

[tex]\[ \text{Area} = \frac{48.092}{2} = 24.246 \, \text{cm}^2 \][/tex]

Finally, we round this result to the nearest tenth:

[tex]\[ 24.246 \, \text{cm}^2 \approx 24.2 \, \text{cm}^2 \][/tex]

Thus, the area of the equilateral triangle, rounded to the nearest tenth, is:

[tex]\[ 24.2 \, \text{cm}^2 \][/tex]

Therefore, the correct answer is [tex]\(24.2 \, \text{cm}^2\)[/tex].

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