Congruent triangles have the exact same three sides and the exact same angles. They are identical. So if you look at your triangles carefully, they are congruent. :)
The answer is 12, hope this helps
Given that,
Sample size= 83
Mean number= 39.04
Standard deviation= 11.51
We know the critical t-value for 95% confidence interval which is equal to 1.989.
We also know the formula for confidence interval,
CI=( mean number - critical t-value*standard deviation/(sample size)^(1/2), mean number + critical t-value*standard deviation/(sample size)^(1/2))
So, we have
CI= (39.04 - 1.989*11.51/83^(1/2), 39.04 + 1.989*11.51/83^(1/2)
CI= (39.04 - 2.513,39.04 + 2.513)
CI= (36.527,41.553)
Therefore, 95% confidence interval for these data is (36.527,41.553), and this result interpret that the true value for this survey sample lie in the interval (36.527,41.553).
<h2><u>Solution</u> :-</h2>
Height of Eric = 6 + 1/6 feet
= 37/6 feet
Height of his brother = 5 + 3/4 feet
= 23/4 feet
Difference between their height :
= 37/6 - 23/4
= (74 - 69)/12
= 5/12
<u>Hence</u>,
Eric is 5/12 feet taller than his brother.
