Solution: The missing reason in Step 8 is substitution of
.
Explanation:
The given steps are used to prove the formula for law of cosines.
From step 5 it is noticed that our equation is
..... (1)
From step 7 it is noticed that the value of
is
.
So by substituting
for
in equation (1) we get the equation of step 8, i.e.,

Hence, the missing reason in Step 8 is substitution of
.
YOU DON"T HAVE TO YELL
512 PER STUDENT
BASICALLY,
CUBES NEEDED=CUBES PER STUDENT TIMES NUMBER OF STUDENTS
NUMBER OF STUDENTS=28+25=53
CUBES PER STUDENT=512
CUBES NEEDED=512 TIMES 53 EQUALS 27136 CUBES
SHE NEEDS 27136 CUBES FOR ALL HER STUDENTS
Answer:

Step-by-step explanation:
For this case we want to find this probability:

Because they want the area to the left of the value. We need to remember that the normal standard distribution have a mean of 0 and a deviation of 1.
We can use the following excel code: =NORM.DIST(-1.55,0,1,TRUE)
And we got:

The other possibility is use the normal standard table and we got a similar result.