X>7
https://quickmath.com/webMathematica3/quickmath/inequalities/solve/basic.jsp#c=solve_stepssolveinequ...
Answer:
The 98% confidence interval for the average credit card balance is
(564.04, 635.96).
Step-by-step explanation:
We have to calculate the 98% confidence interval on the average credit card balance.
The sample will consist of the n=30 customers that have credit card.
The sample has a mean of $600 and a standard deviation of $80.
As the population standard deviation is estimated from the sample standard deviation, we will use a t statistic.
The degrees of freedom are:

The critical value for a 98% CI and 29 degrees of freedom is t=2.463 (this can be looked up in a t-table).
Then, the margin of error is:

Then, the upper and lower bounds of the confidence interval are:

Answer:
Step-by-step explanation:
Let the side of the triangle be s, since it is equilateral, all three angles measure s.
<u>Now, if we connect A and D, we get two triangles:</u>
<u>Find the area of each triangle:</u>
- A = 1/2bh
- A(ΔABD) = 1/2s(RD) = 1/2s*4 = 2s
- A(ΔACD) = 1/2s(DT) = 1/2s*8 = 4s
<u>The sum of the areas is the area of ΔABC:</u>
<u>Now, assume the height of ABC is h, find its area:</u>
<u>Compare this with the sum of areas and solve for h:</u>
- 6s = 1/2sh
- 6 = 1/2h
- 12 = h
- h = 12