Respuesta :

Hi1315

Answer:

[tex]12.56m[/tex]

4th answer is correct.

Step-by-step explanation:

[tex] \frac{180}{360} \times 2\pi \: r \\ \frac{1}{2} \times 2 \times \pi \times 4 \\ = 12.56m[/tex]

we know the circumference of circle which

2pir

then circumference of semi circle is

2pir×1/2

where 2 and 2 get cancel

and we are left with pir

so.. pi4

=12.56