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Finding the Fourth Proportional to 659.92, 989.92 and 385.80

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Solution

The fourth proportional to 659.92, 989.92 and 385.80 is: 578.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    659.92 : 989.92 = 385.80 : x
  2. Step 2: Convert to fraction form
    659.92/989.92 = 385.80/x
  3. Step 3: Cross multiply
    659.92x = 989.92 × 385.80
  4. Step 4: Simplify right side
    659.92x = 381,911.14
  5. Step 5: Solve for x
    x = 381,911.14/659.92
  6. Step 6: Final answer
    x = 578.72

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.