Given:
.
To find:
The value of r.
Solution:
We have,
.
We know that the radius is perpendicular to the tangent at the point of tangency
AD is the tangent and CD is the radius. So, CD is perpendicular to AD at point D, i.e., 
.
Using Pythagoras theorem, we get
On further simplification, we get
Therefore, the value of r is 9.
one pump, let's call it A, fills the reservoir by 1/60 every hour. Now, B fills it by 1/80 every hour. C empties it by 1/90 every hour. All three are on, so now we combine them into one function: t(1/60 + 1/80 - 1/90) = 1, where t = the time it takes to fill it, and 1 is just our "reservoir finally filled" marker.
isolate t onto one side and we see t = 720/13 exactly, or approximately 55.38 hours. let me know if this is the wrong answer but I'm pretty sure it is correct!
Answer:
13.38
Step-by-step explanation:
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Answer:
D.the treatment group (placebo or reading strategies)
Step-by-step explanation:
This cognitive psychologists wants to find out if better reading strategies when taught to students would have any effect on their test scores.
So the dependent variable in this experiment would be the test scores that she wants to find from the test.
While the independent variable would be the treatment group which is the placebo or treatment. The psychologist wants to measure outcomes in this dependent variable using changes in the independent variable (placebo/treatment).
