12: twelve
1 rod(10 blocks)
2 cubes(2 singles blocks)
Answer:
A score of 150.25 is necessary to reach the 75th percentile.
Step-by-step explanation:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean
and standard deviation
, the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
A set of test scores is normally distributed with a mean of 130 and a standard deviation of 30.
This means that 
What score is necessary to reach the 75th percentile?
This is X when Z has a pvalue of 0.75, so X when Z = 0.675.




A score of 150.25 is necessary to reach the 75th percentile.
Step-by-step answer:
This is a regular heptagon, means it has 7 <em>congruent</em> sides and 7 <em>congruent </em>vertex angles.
To work with polygons, there is a very important piece of information that you must know to solve the majority of related problems.
This is:
sum of exterior angles of polygons = 360 degrees.
If you don't remember the 360 degrees, think of the sum of exterior angles of an equilateral triangle, which is 3*(180-60)=3*120=360! It works!
For a regular heptagon, c = 360/7=51.43 degrees approx.
This means that each vertex angle measures
vertex angle = 180-c
So since 2d+the vertex angle = 360, we have
2d+(180-c)=360
solve for d:
2d=360-(180-c)=180+c
d=(180+c)/2=90+c/2=115.71 degrees. (approx.)