Math Problem Statement

Do number 6

How many times do we need to fill the cube in order to fill the cone completely with water? (Use π = 3.)

Solution

To solve question 6 from the image, let us break it down step by step.


Problem:

  • A cone has a radius of 6 cm and a height of 6 cm.
  • A cube has an edge length of 6 cm.
  • We need to find how many times the cube needs to be emptied to fill the cone completely with water.

Step 1: Volume of the cone

The formula for the volume of a cone is:
Vcone=13πr2hV_{\text{cone}} = \frac{1}{3} \pi r^2 h
Where:

  • r=6cmr = 6 \, \text{cm} (radius)
  • h=6cmh = 6 \, \text{cm} (height)
  • π=3\pi = 3 (as stated in the question)

Substitute the values: Vcone=13×3×62×6V_{\text{cone}} = \frac{1}{3} \times 3 \times 6^2 \times 6 Vcone=13×3×36×6V_{\text{cone}} = \frac{1}{3} \times 3 \times 36 \times 6 Vcone=36×6=216cm3V_{\text{cone}} = 36 \times 6 = 216 \, \text{cm}^3

So, the volume of the cone is: 216cm3216 \, \text{cm}^3


Step 2: Volume of the cube

The formula for the volume of a cube is:
Vcube=a3V_{\text{cube}} = a^3
Where a=6cma = 6 \, \text{cm} (edge length).

Substitute the value: Vcube=63=216cm3V_{\text{cube}} = 6^3 = 216 \, \text{cm}^3

So, the volume of the cube is: 216cm3216 \, \text{cm}^3


Step 3: Calculate how many cubes are needed to fill the cone

The volume of the cone and the cube are equal (216cm3216 \, \text{cm}^3). This means 1 cube is enough to completely fill the cone.


Final Answer:

1 cube is needed to fill the cone.\boxed{1 \text{ cube is needed to fill the cone.}}


Would you like further clarification or a detailed explanation of the concepts? Here are 5 related questions:

  1. How is the volume formula for a cone derived?
  2. How does the cube's edge length relate to its volume?
  3. What happens if the cone's height or radius changes?
  4. Why is π=3\pi = 3 used instead of the more accurate value?
  5. Can you calculate the total surface area of the cube and cone?

Tip:

Always compare the units of volume carefully when working with different shapes to ensure consistency.

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Math Problem Analysis

Mathematical Concepts

Volume of a cone
Volume of a cube

Formulas

Volume of a cone: V = (1/3)πr²h
Volume of a cube: V = a³

Theorems

Volume formula for 3D shapes

Suitable Grade Level

Grades 6-8