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Finding the Fourth Proportional to 989.57, 1,484.87 and 405

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Solution

The fourth proportional to 989.57, 1,484.87 and 405 is: 607.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.57 : 1,484.87 = 405 : x
  2. Step 2: Convert to fraction form
    989.57/1,484.87 = 405/x
  3. Step 3: Cross multiply
    989.57x = 1,484.87 × 405
  4. Step 4: Simplify right side
    989.57x = 601,370.33
  5. Step 5: Solve for x
    x = 601,370.33/989.57
  6. Step 6: Final answer
    x = 607.71

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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.