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Finding the Fourth Proportional to 489.92, 676.16 and 392.40

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Solution

The fourth proportional to 489.92, 676.16 and 392.40 is: 541.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    489.92 : 676.16 = 392.40 : x
  2. Step 2: Convert to fraction form
    489.92/676.16 = 392.40/x
  3. Step 3: Cross multiply
    489.92x = 676.16 × 392.40
  4. Step 4: Simplify right side
    489.92x = 265,325.18
  5. Step 5: Solve for x
    x = 265,325.18/489.92
  6. Step 6: Final answer
    x = 541.57

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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.