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Finding the Fourth Proportional to 489.47, 674.07 and 390.92

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Solution

The fourth proportional to 489.47, 674.07 and 390.92 is: 538.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    489.47 : 674.07 = 390.92 : x
  2. Step 2: Convert to fraction form
    489.47/674.07 = 390.92/x
  3. Step 3: Cross multiply
    489.47x = 674.07 × 390.92
  4. Step 4: Simplify right side
    489.47x = 263,507.44
  5. Step 5: Solve for x
    x = 263,507.44/489.47
  6. Step 6: Final answer
    x = 538.35

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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.