Answer:
D) 5
Step-by-step explanation:
a²+b²=c²
12²+b²=13²
144+b²=169
b²=169-144
b²=25
b=√25
b=5
For each power of ten , the number of zeros written in the product is the same as the number of exponents.
Answer:
The 98% confidence interval estimate of the proportion of adults who use social media is (0.56, 0.6034).
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.

In which
z is the zscore that has a pvalue of
.
Of the 2809 people who responded to survey, 1634 stated that they currently use social media.
This means that 
98% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
The lower limit of this interval is:

The upper limit of this interval is:

The 98% confidence interval estimate of the proportion of adults who use social media is (0.56, 0.6034).
For an investment compounded continuously, the rule of 69 gives a better approximation than the rule of 72 (for normal compound interests).