The only choice with the correct denominator is

_____
For multiple choice questions, it works well to eliminate answers that cannot possibly be right, then look at what remains. Here, only one answer remains.
Answer:
The density is 787 kg/m³
Step-by-step explanation:
The formula of density is d =
, where M is the mass and v is the volume
The formula of the volume of a cylinder is V = πr²h, where r is the radius of its base and h is its height
∵ The American white oak tree is shaped a cylinder
∵ Its radius is 0.7 m
∴ r = 0.7 m
∵ Its height is 8 m
∴ h = 8 m
- Substitute the values of r and h in the volume formula
∵ V = π(0.7)²(8)
∴ V = 3.92π m³
∴ The volume of the American white oak tree is 3.92π m³
∵ The mass of the American white oak tree is 9694 kg
∴ M = 9694 kg
- Substitute the values of M and V in the formula of density
∵ d = 
∴ d = 787.1674
- Round it to the nearest whole number
∴ d = 787 kg/m³
The density is 787 kg/m³
Solution
To solve division problems you can make equal groups
Example
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It is
ΔABO is a right triangle with AB⊥BO. The radius of the circle is BO. The Pythagorean theorem applies.
AO² = AB² + BO²
13² = 5² + r²
169 -25 = r²
r = √144 = 12
The radius (r) is 12.
Answer:
Validation
Step-by-step explanation: Validation is a term used to describe the processes involved when we compare a set of values and observations against a set standard or rules to ensure that they meet certain expectations or criteria.
Validation is meant to prove that something, a data set etc are acceptable based on known rules, the rules or standards which is used to evaluate what can be described as valid.