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Finding the Fourth Proportional to 485.61, 670.56 and 392.86

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Solution

The fourth proportional to 485.61, 670.56 and 392.86 is: 542.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    485.61 : 670.56 = 392.86 : x
  2. Step 2: Convert to fraction form
    485.61/670.56 = 392.86/x
  3. Step 3: Cross multiply
    485.61x = 670.56 × 392.86
  4. Step 4: Simplify right side
    485.61x = 263,436.20
  5. Step 5: Solve for x
    x = 263,436.20/485.61
  6. Step 6: Final answer
    x = 542.49

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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.