About 68% of sixth-grade students will have heights between inches and inches.

About 68% of sixth-grade students will have heights between 55.7 inches and 60.3 inches.

Step-by-step explanation:

The Empirical rule, also the 68–95–99.7 rule, states that for a population that is approximately normal or symmetrical, nearly all of the data values will lie within three standard deviations of the mean;

68% of data values will fall within one standard deviation from the mean

95% of data values will fall within two standard deviation from the mean

99.7% of data values will fall within three standard deviation from the mean

Now, assuming the heights of the sixth-grade students are approximately normal 68% of these students will have their heights fall within one standard deviation from the mean;

mean ± standard deviation

58 ± 2.3 = (55.7, 60.3)

Therefore, about 68% of sixth-grade students will have heights between 55.7 inches and 60.3 inches.

the height of the surface increases from the center out to the sides of the road.

step-by-step explanation:

as we move out we move away from the x-axis.

and as mentioned in the problem statement that height of a road increases when we move away from the center x.

hence proved that 3rd option

the height of the surface increases from the center out to the sides of the road.

is the correct option.