The most economical proportion for a right circular cone is to have its height three times long as its base diameter. What lateral area of the cone would produce a volume of 100m^3.

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Answer:

  ∛(2500π)√37 m² ≈ 120.911 m²

Step-by-step explanation:

If the height is 3 times the diameter, it is 6 times the radius. Then the volume is ...

  V = 1/3πr²h

  V = 1/3πr²(6r) = 2πr³

For a volume of 100 m³, the radius is ...

  100 m³ = 2πr³

  r = ∛(50/π) m

The lateral area of the cone is computed from the slant height. For this cone, the slant height is found using the Pythagorean theorem:

  s² = r² +(6r)² = 37r²

  s = r√37

Then the lateral area is ...

  LA = πrs

  LA = π(∛(50/π) m)(∛(50/π) m)√37

  LA = ∛(2500π)√37 m² ≈ 120.911 m²

The lateral area of the economical cone with a volume of 100 m³ is 120.911 m².

What is the lateral area of the cone?

The lateral area of the cone is the curved area of the cone, therefore, the total area of the cone is without the base area.

As we know that the volume of the cone is given by the formula,

[tex]V = \dfrac{1}{3}\pi r^2h[/tex]

Now, for the right circular cone to be economical, the height must be 3 times the diameter or it should be 6 times the radius. Therefore, the economical volume can be written as,

 [tex]V = \dfrac{1}{3}\pi r^2h\\\\V = \dfrac{1}{3}\pi r^2(6r)[/tex]

Now, if cancel out the 3 in the remainder with the six in the numerator, the volume of the cone can be written as,

[tex]V = 2\pi r^3[/tex]

Further, we need to calculate the lateral area of the cone, whose volume is 100 m³. Now, in order to get the radius of the economic cone with the volume of 100 m³, substitute it with 2πr³,

[tex]V = 2\pi r^3\\\\100 = 2\pi r^3\\\\r = 2.5154\rm\ m[/tex]

We know that in order to calculate the lateral area of the cone we need to calculate the slant height. Thus, according to the Pythagorean theorem, the slant height can be written as

[tex]s^2 = r^2 +(6r)^2\\\\ s^2 = 37r^2\\\\ s = r\sqrt{37}[/tex]

Now, the lateral area of the economical cone with the volume of 100 m³ can be written as,

[tex]LA = \pi rs\\\\LA = \pi \times r \times r\sqrt{37}\\\\LA = \pi \times r^2 \times \sqrt{37}\\\\LA = \pi \times (2.5154)^2 \times \sqrt{37}\\\\LA = 120.911\rm\ m^2[/tex]

Hence, the lateral area of the economical cone with a volume of 100 m³ is 120.911 m².

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