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Finding the Fourth Proportional to 728.71, 1,005.65 and 489.76

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Solution

The fourth proportional to 728.71, 1,005.65 and 489.76 is: 675.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    728.71 : 1,005.65 = 489.76 : x
  2. Step 2: Convert to fraction form
    728.71/1,005.65 = 489.76/x
  3. Step 3: Cross multiply
    728.71x = 1,005.65 × 489.76
  4. Step 4: Simplify right side
    728.71x = 492,524.02
  5. Step 5: Solve for x
    x = 492,524.02/728.71
  6. Step 6: Final answer
    x = 675.89

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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.