Calculate Cuboid Length: Volume 96 cm³ with 3:2 Ratio and Height 4 cm

Volume Formulas with Length-Width Ratios

A cuboid has a height of 4 cm.

The ratio between its length and its width is 3:2.

The volume of the cuboid is equal to 96 cm³.

Calculate the length of the cuboid.

444

❤️ Continue Your Math Journey!

We have hundreds of course questions with personalized recommendations + Account 100% premium

Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:13 Let's find the length of the box.
00:16 Here's the ratio of the edges based on the data given.
00:23 We'll call the unknown value X.
00:30 Let's use the formula to calculate the box's volume.
00:35 That's width times height times length.
00:38 Now, put the right values in the formula and solve for X.
01:04 We need to get X by itself.
01:18 This gives us X. It must be positive since it's an edge length.
01:23 Use the X value to determine the box's length.
01:33 And there you go! That's the solution.

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

A cuboid has a height of 4 cm.

The ratio between its length and its width is 3:2.

The volume of the cuboid is equal to 96 cm³.

Calculate the length of the cuboid.

444

2

Step-by-step solution

To solve this problem, we need to find the length of the cuboid using its volume and given dimensions. Let's break this down:

  • Step 1: Express the length and width using the ratio given. Let l=3x l = 3x and w=2x w = 2x , where x x is a common factor.
  • Step 2: Apply the formula for the volume of the cuboid, V=l×w×h V = l \times w \times h . Given that h=4 h = 4 cm and V=96 V = 96 cm³, the equation becomes:
96=(3x)×(2x)×4 96 = (3x) \times (2x) \times 4

Now, simplify and solve for x x :

96=24x2 96 = 24x^2

Dividing both sides by 24 gives:

x2=4 x^2 = 4

Taking the square root of both sides, we find:

x=2 x = 2

Thus, the length of the cuboid is:

l=3x=3×2=6 cm l = 3x = 3 \times 2 = 6 \text{ cm}

Therefore, the solution to the problem is 6 cm 6 \text{ cm} .

3

Final Answer

6 cm

Key Points to Remember

Essential concepts to master this topic
  • Volume Formula: For cuboids, V = length × width × height
  • Ratio Method: Let length = 3x and width = 2x when ratio is 3:2
  • Check: Verify 6 × 4 × 4 = 96 cm³ matches given volume ✓

Common Mistakes

Avoid these frequent errors
  • Using the ratio directly as actual measurements
    Don't assume length = 3 cm and width = 2 cm just from 3:2 ratio = volume of only 24 cm³! The ratio shows proportions, not actual sizes. Always use variables like 3x and 2x, then solve for x using the volume formula.

Practice Quiz

Test your knowledge with interactive questions

Calculate the volume of the rectangular prism below using the data provided.

888333222

FAQ

Everything you need to know about this question

Why can't I just use 3 and 2 as the length and width?

+

The ratio 3:2 tells us the proportion, not the actual measurements! If length was 3 cm and width was 2 cm, the volume would be 3×2×4=24 3 \times 2 \times 4 = 24 cm³, not 96 cm³.

How do I set up the variables from the ratio?

+

When the ratio is 3:2, let length = 3x and width = 2x. The variable x is a scale factor that makes the measurements fit the actual volume.

What if I get a negative value for x?

+

Since we're dealing with lengths, x must be positive. If you get a negative square root, double-check your equation setup and calculations.

Can I solve this without using variables?

+

Using variables with ratios is the most reliable method. Guessing and checking might work, but it's time-consuming and you might miss the correct answer.

How do I know which dimension is length vs width?

+

In this problem, it doesn't matter! Since we multiply length × width, getting 6 cm and 4 cm gives the same volume whether 6 is length or width.

What's the fastest way to check my answer?

+

Substitute back: 6×4×4=96 6 \times 4 \times 4 = 96 cm³. Also verify the ratio: 6:4=3:2 6:4 = 3:2

🌟 Unlock Your Math Potential

Get unlimited access to all 18 Cuboids questions, detailed video solutions, and personalized progress tracking.

📹

Unlimited Video Solutions

Step-by-step explanations for every problem

📊

Progress Analytics

Track your mastery across all topics

🚫

Ad-Free Learning

Focus on math without distractions

No credit card required • Cancel anytime

More Questions

Click on any question to see the complete solution with step-by-step explanations