Answer:
1. 
2. 3.2362
3. 
Step-by-step explanation:
1.
Cot is the trigonometric ratio defined by "adjacent" over "opposite". <em>So, adjacent = 2 and opposite = 3.</em>
By pythagorean theorem, we have the "hypotenuse" as 
Csc is defined as the trig ratio "hypotenuse" over "opposite". <em>We know the sides, so Csc
=
</em>
<em />
<em>First answer choice is right.</em>
<em />
2.
By definition, Csc
is the inverse of Sine
. <em>If given the value of sin theta, to find value of csc theta, we take the reciprocal of it. Hence:</em>

Third answer choice is right.
3.
By definition tan and cot are inverse of each other. <em>So the value of tan is the reciprocal of the value of cot.</em> We can simply "flip" the value of tan theta to get the value of cot theta. Hence:

Third answer is right.
This question seems to me to be an exercise in applying the rule for a difference of squares in order to rewrite the difference of two relatively large numbers as the "simpler" product of other integers.
Answer:
No, it isn't.
Step-by-step explanation:
Pythagorean theorem is x^2 + y^2 = z^2.
6^2 + 8^2 = 9^2
36 + 64 = 81
100 = 81
So, it isn't.