The standard equation for a parabola that opens upward parallel to the y-axis is x2=4ay, where a = distance from the vertex to focus. Vertex is at origin(0,0)
4a=2
a=2/4
a=1/2 or 0.5
the coordinate of the focus is (0, 1/2)
the equation of the directrix is y=-1/2
Tammy's sample may not be considered valid because, on the first hand, it is said that she only asked students from her " Math Class".
If she wants to have a survey to find out the favorite subject of the students at her school, she must conduct a survey involving all the students in her school, not just in her class. What she did is just subjective. She should use a tally listing the different subjects and compare the number of students per subject. This way, she can have an objective representation of the least liked subjects and the most liked subjects of the students on her school.
Illustrating her survey through statistics may be more reliable and valid because it shows frequencies in which she can calculate easily and accurately the percentage of the number of students per subject, in a more objective manner.
-1/2 = -3/6
-3/6 + 1/6 = -2/6
-2/6 = -1/3
-1/3 is your answer
hope this helps
Answer:
The height of the triangle is 
cm.
Step-by-step explanation:
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The formula for solving the area of a triangle is 
where 
stands for base and 
stands for height.
Let's substitute 30 
for the area and 10 for the base.
-------------------->>>>
Now, let's solve to find the height.
Multiply 
times 
Divide both sides by 5.
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Hope this is helpful.
