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Finding the Fourth Proportional to 1,319.67, 1,979.77 and 909

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Solution

The fourth proportional to 1,319.67, 1,979.77 and 909 is: 1,363.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,319.67 : 1,979.77 = 909 : x
  2. Step 2: Convert to fraction form
    1,319.67/1,979.77 = 909/x
  3. Step 3: Cross multiply
    1,319.67x = 1,979.77 × 909
  4. Step 4: Simplify right side
    1,319.67x = 1,799,610.93
  5. Step 5: Solve for x
    x = 1,799,610.93/1,319.67
  6. Step 6: Final answer
    x = 1,363.68

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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.