Geometry Rule: SOH CAH TOA.
Sine = opposite over hypotenuse
Cosine = adjacent over hypotenuse
Tangent = opposite over hypotenuse
I won't solve all of these for you because I find that solving it on your own is an important step in learning to actually understand how this works.
Since you didn't provide the choices, I can only give you some help. Then, you can select the correct choices.
The converse of the Pythagorean Theorem is when the square of the longest side of a triangle is equal to the sum of the squares of the two other sides for a triangle ABC with sides of a, b, c, then triangle ABC is a right triangle.
This is the way I got it the answer is v= 45
Area=pi times radius^2 so
if area=4pi=pi times r^2
4 times pi=r^2 times pi
divide both sdies by pi
4=r^2
square root
2=radius since legnth cannot be negative
radius=1/2 diamters
2 radius=diameter
2(2)=diameter=4
diameter=4
