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Finding the Fourth Proportional to 491.78, 674.12 and 489.62

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Solution

The fourth proportional to 491.78, 674.12 and 489.62 is: 671.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    491.78 : 674.12 = 489.62 : x
  2. Step 2: Convert to fraction form
    491.78/674.12 = 489.62/x
  3. Step 3: Cross multiply
    491.78x = 674.12 × 489.62
  4. Step 4: Simplify right side
    491.78x = 330,062.63
  5. Step 5: Solve for x
    x = 330,062.63/491.78
  6. Step 6: Final answer
    x = 671.16

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.