Uma pessoa com audição normal pode ouvir sons de frequências entre 20 Hz e 20000 Hz. As frequências das ondas de rádio ficam entre 3000 Hz a 300 GHz. (1 GHz = 1000000000 Hz). Se 10000 Hz, por exemplo, é uma frequência audível, por que as pessoas não ouvem as ondas de rádio que estão viajando no espaço que rodeia?

pentagon

step-by-step explanation:

the coordinates   a(5, -2), b(3,-1),c(-4,-4) d(-3,8) and e(-1,4) forms the vertices of the polygon when they are connected in order.

in order to classify that which polygon is it with the given coordinates, first count the number of vertices and then count the number of sides it can make with these vertices.

since, the given coordinates have five vertices, therefore, it will make five sides. moreover, pentagon is regular in nature therefore it will be convex.

now, a polygon with five sides is known as pentagon, therefore, the given polygon is the pentagon.

9 sandwiches per hour

step-by-step explanation:

when we have a rate, we want a 1 in the denominator

27/3 = 9

27 sandwiches/ 3 hours = 9 sandwiches/hour

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step-by-step explanation: