36
Step-by-step explanation:
We know that
- Sum of two complementary angles is 90°
- Let the other angle be x
<h3>So</h3><h3>

</h3>
According to the vertex and the directrix of the given parabola, the equation is:

<h3>What is the equation of a parabola given it’s vertex?</h3>
The equation of a quadratic function, of vertex (h,k), is given by:

In which a is the leading coefficient.
The directrix is at y = k + 4a.
In this problem, the vertex is (1,4), hence:

The directrix is at y = 7, hence:


Hence, the equation is:


More can be learned about the equation of a parabola at brainly.com/question/26144898
Answer:
21
Step-by-step explanation:
He will guess correctly 25% of the time.
He has 84 questions
25% of 84
.25 * 84
21
We should expect that he will get 21 questions correct
The answer is 343
Because volume is length x width x height which would be 7 x 7 x 7