Find the area of a regular pentagon with an apothem of 11 units. *
364 square units
O 440 square units
516 square units
O 166 square units

Respuesta :

Answer:

440 square units

Step-by-step explanation:

We can find half of a side of the pentagon with the expression

[tex]tan(36\°)=\frac{s_{half} }{11}[/tex]

Because, as a regular polygon, all its sectors have the same central angle, and the apothem divides equally each sector in two equal parts.

[tex]s_{half} \approx 8[/tex]

Therefore, half of a side is 8 units long, which means each side measures 16 units.

Now, the area of a penthagon is defined by

[tex]A=\frac{p \times a}{2}[/tex]

Where [tex]p[/tex] is the perimeter and [tex]a[/tex] is the apothem. Where the perimeter is the sum of all sides, which is 80 units.

[tex]A= \frac{80 \times 11}{2} =440 \ u^{2}[/tex]

Therefore, the right answer is the second choice.