The answer is 120 degrees
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 area of a triangle is 1/2 b/h. So what you do is you find base and height, multiply them together and whatever answer you got, you divide by 2.
Example:
A= 1/2 (b x h)
A= 1/2 (4 x 6)
A= 1/2 (24)
A= 12
Hope this helps!
1. C - You could add 6 and divide by negative three with this one
2. B - By plugging in five, you would get 9-10. and that would give you -1
3. B - You would add 18 to 12 to get 30