Calculate Water Height: Finding Level in 125 cm³ Cube with 75 cm³ Water

Question

A cube has a volume equal to 125 cm3.

If we pour 75 cm³ of water into it, how high will the water reach?

Video Solution

Solution Steps

00:00 To what height will the water reach?
00:03 We'll use the formula for volume calculation (edge cubed)
00:07 We'll extract the cube root
00:12 This is the size of edge A
00:22 The height of the cube is the edge
00:27 We'll calculate the volume ratio
00:31 This is the volume ratio
00:34 The volume ratio equals the height ratio
00:38 We'll multiply the height by the ratio to find the water height
00:42 And this is the solution to the question

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Calculate the side length of the cube.
  • Step 2: Find the base area of the cube.
  • Step 3: Determine the height the water reaches based on its volume.

Now, let's work through each step:

Step 1: The volume of the cube is 125cm3 125 \, \text{cm}^3 . Since the volume of a cube is given by s3 s^3 , we have:

s3=125 s^3 = 125

Taking the cube root of both sides gives:

s=1253=5cm s = \sqrt[3]{125} = 5 \, \text{cm}

Step 2: The base area of the cube is s2 s^2 , which is:

(5cm)2=25cm2 (5 \, \text{cm})^2 = 25 \, \text{cm}^2

Step 3: The volume of water is 75cm3 75 \, \text{cm}^3 , and we need to find the height h h it reaches in the cube:

75=25×h 75 = 25 \times h

Solving for h h :

h=7525=3cm h = \frac{75}{25} = 3 \, \text{cm}

Therefore, the height to which the water will reach is 3cm 3 \, \text{cm} .

Answer

3 3 cm


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