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Finding the Fourth Proportional to 318.72, 439.68 and 291.36

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Solution

The fourth proportional to 318.72, 439.68 and 291.36 is: 401.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.72 : 439.68 = 291.36 : x
  2. Step 2: Convert to fraction form
    318.72/439.68 = 291.36/x
  3. Step 3: Cross multiply
    318.72x = 439.68 × 291.36
  4. Step 4: Simplify right side
    318.72x = 128,105.16
  5. Step 5: Solve for x
    x = 128,105.16/318.72
  6. Step 6: Final answer
    x = 401.94

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.