An employee at a fireworks company is designing a rocket. The rocket will consist of a cardboard circular cylinder with a height that is seven times as large as the radius. On top of the cylinder will be a cone with a height of 5 in. and a radius equal to the radius of the base as shown in the figure. If the company wants to fill the cone and the cylinder with a total of 204 in.^3 of​ powder, then what should be the radius of the​ cylinder? Note that the volume of a right circular cylinder with radius r and height h is and the volume of a cone with a base of radius r and height h is .

Respuesta :

The radius of the cylinder should be approximately 2.040 inches long.

How to calculate the radius of a rocket to contain a required quantity of powder

The volume required to store the powder is the sum of the volumes of the cylinder and the cone, whose expression is in this case:

204 in³ = (π/3) · r² · (4 in) + π · r² · h

204 in³ = (4/3 + h) · π · r²

204 in³ = (4/3 + 7 · r) · π · r²

204 = (4π/3) · r² + 7π · r³

7π · r³ + (4π/3) · r² - 204 = 0

The positive roots of the cubic equation are:  

r ≈ 2.040 in

The radius of the cylinder should be approximately 2.040 inches long.

To learn more on volumes: https://brainly.com/question/1578538

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