What we know is that the sum of a triangle's internal angles are 180º, and a straight angle makes 180º.
first, we have to find the third internal angle(let's call it n) so that we can use it to find the exterior angle.
(3x + 20) + (4x + 5) + n = 180
simplify:
7x + 25 + n = 180
7x + n = 155
n = 155 - 7x
Now we can add it to the external angle to find x.
(155 - 7x) + (8x + 15) = 180
simplify:
170 + 8x - 7x = 180
170 + x = 180
x = 10
Now we can substitute it to the external angle.
8 x 10 + 15 = 95
the exterior angle is 95º.
Answer:

Step-by-step explanation:
Given
-- degree of freedom

Required
Determine the t-value
The given parameters can be illustrated as follows:

Where

So, we have:

To solve further, we make use of the attached the student's t distribution table.
From the attached table,
The t-value is given at the row with df = 28 and
is 3.673900
Hence, 
The correct answer you need will equal 9
Answer:

Step-by-step explanation:
We are given the following in the question:
Sample size, n = 67
Variance = 3.85
We have to find 80% confidence interval for the population variance of the weights.
Degree of freedom = 67 - 1 = 66
Level of significance = 0.2
Chi square critical value for lower tail =

Chi square critical value for upper tail =

80% confidence interval:

Putting values, we get,

Thus, (3.13,4.91) is the required 80% confidence interval for the population variance of the weights.
-18/3
18/(-3)
<h2>
Explanation:</h2>
The complete question is as follows:
________________________________________________
Which expression best estimates -18 1/4 divided by 2 2/3?
18/3
-18/3
-18/(-3)
18/(-3)
________________________________________________
So in this exercise, we have two mixed fractions. This type of fractions comes from the combination of a whole number and a proper fraction fraction (numerator less than denominator). In order to solve this problem, we need to transform these mixed fractions into improper fractions (numerator greater than denominator). So:


By dividing:

<em>So the expressions that best estimates -18 1/4 divided by 2 2/3 are:</em>
<em>-18/3
</em>
<em>18/(-3)</em>
<em>Whose value in decimal form is -6.0</em>
<h2 /><h2>Learn more:</h2>
Estimate the distance between cities: brainly.com/question/12062666
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