Explanation:
If the polyhedron is a prism and the cross sections are parallel to the base, then the cross section will match the base. Under other conditions, the cross section may not match the base.
For example, the first attachment is a figure of a cube. Cross sections are shown that have the shape of a triangle, trapezoid and hexagon. Other cross sections are possible.
A general polyhedron need not be regular and need not have any cross section congruent to the base (except the cross section that <em>is</em> the base). For some polyhedrons, it may be difficult even to identify the base. See the second attachment.
Equation
Because expressions don't contain equal signs
Answer:
Step-by-step explanation:
To factor this, you must first take out the GCF (Greatest Common Factor), that 
and -147 both have. The terms only have 3 in common, which can be divided with
However, we're still not done since 49 is a perfect square and 
can be split into 2, like so:
If you're unsure about the final answer, you can multiply it all together to see if you got the original expression.
Answer:
By the Empirical Rule, 99.7% of the students have grade point averages that are between 1.28 and 3.8.
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed(bell-shaped) random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 2.54
Standard deviation = 0.42.
Between 1.28 and 3.8?
1.28 = 2.54 - 3*0.42
So 1.28 is 3 standard deviations below the mean
3.8 = 2.54 + 3*0.42
So 3.8 is 3 standard deviations above the mean
By the Empirical Rule, 99.7% of the students have grade point averages that are between 1.28 and 3.8.
