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Finding the Fourth Proportional to 665.78, 999.02 and 392.40

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Solution

The fourth proportional to 665.78, 999.02 and 392.40 is: 588.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.78 : 999.02 = 392.40 : x
  2. Step 2: Convert to fraction form
    665.78/999.02 = 392.40/x
  3. Step 3: Cross multiply
    665.78x = 999.02 × 392.40
  4. Step 4: Simplify right side
    665.78x = 392,015.45
  5. Step 5: Solve for x
    x = 392,015.45/665.78
  6. Step 6: Final answer
    x = 588.81

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.