She has made 28 snowflakes.
Using the binomial distribution, it is found that there is a 0.0555 = 5.55% probability that more than 3 of these selected children have three siblings.
<h3>What is the binomial distribution formula?</h3>
The formula is:


The parameters are:
- x is the number of successes.
- n is the number of trials.
- p is the probability of a success on a single trial.
In this problem, for the parameters, we consider that:
- 10% of the 9-year old children in a town have three siblings, hence p = 0.1.
- Fifteen 9-year old children are selected at random, hence n = 15.
The probability that more than 3 of these selected children have three siblings is given by:

In which:

Then:






P(X > 3) = 1 - 0.9445 = 0.0555
0.0555 = 5.55% probability that more than 3 of these selected children have three siblings.
More can be learned about the binomial distribution at brainly.com/question/24863377
Answer:
x = 4
8(4) - 2 = 30
15(4) = 60
All triangles equal 180 degrees and there is already a right angle. 60 plus 0 is 90, and 90 plus 90 (or 90 times 2) is 180
60 + 30 = 90
90 + 90 = 180
Step-by-step explanation: