B Why Is a Cubic Polynomial Called 'Third Degree'?

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A cubic polynomial is called so because it is a third-degree polynomial, analogous to how the volume of a cube is calculated using the formula l^3, where l is the side length. The term "cubic" relates to the three-dimensional nature of a cube, just as "quadratic" refers to the area of a square, which is l^2. The naming convention extends to other polynomial degrees, with quartic for fourth degree and quintic for fifth degree. This terminology reflects the geometric concepts associated with each degree. Understanding these connections clarifies the terminology used in polynomial classification.
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Why is third degree called cubic?
Why is a third degree polynomial called a cubic polynomial? I just don’t see the connection between 3 and a cube.
 
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A cube is a three dimensional object. The volume of a cube is ##l^3##, where ##l## is the side length. That's cubic formula, in both senses.
 
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It's the same reason the second degree is square.
 
Mathsig said:
Why is a third degree polynomial called a cubic polynomial?
Further, a second degree polynomial is called a quadratic polynomial because the area of a square is ##l^2##. The Latin word quadratus means "square."

Other types of polynomials have names such as quartic (fourth degree) and quintic (fifth degree).
 
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Seemingly by some mathematical coincidence, a hexagon of sides 2,2,7,7, 11, and 11 can be inscribed in a circle of radius 7. The other day I saw a math problem on line, which they said came from a Polish Olympiad, where you compute the length x of the 3rd side which is the same as the radius, so that the sides of length 2,x, and 11 are inscribed on the arc of a semi-circle. The law of cosines applied twice gives the answer for x of exactly 7, but the arithmetic is so complex that the...