Alright, so what we can take as a given is that arcDE/2= ∠CDE=2x+20 since the arc corresponding to the angle is 2*the angle. To solve for arcDE, we multiply both sides by 2 to get 2(2x+20)=4x+40=arcDE. Since the arcs in a circle add up to 360 degrees and we only have -20+30x and arcDE, we have -20+40+4x+30x=360 using the associative property. Simplifying, we get 20+34x=340. Subtracting 20 from both sides, we get 340=34x. Next, we can divide both sides by 34 to get 10=x.
The vloume is 5*7*2=70 inch
Answer:
Associative propertry of addition.
Step-by-step explanation:
The associative property of addition states that:

It states that we can add numbers regardless of the groups. The sum does not change irrespective of how the addends are grouped.
We are given the expression:

It can be written as:

It can also be written as:

Whatever maybe the arrangement of r, h and t, their sum will always be equal. We can regroup them in many ways but the sum remains the same.
<u>Part A</u>
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<u>Part B</u>
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<u>Part C</u>
No, because although they provide examples for specific polynomials being closed under addition and subtraction, there is a loss of generality.