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Finding the Fourth Proportional to 1,319.20, 1,979.10 and 771.10

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Solution

The fourth proportional to 1,319.20, 1,979.10 and 771.10 is: 1,156.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,319.20 : 1,979.10 = 771.10 : x
  2. Step 2: Convert to fraction form
    1,319.20/1,979.10 = 771.10/x
  3. Step 3: Cross multiply
    1,319.20x = 1,979.10 × 771.10
  4. Step 4: Simplify right side
    1,319.20x = 1,526,084.01
  5. Step 5: Solve for x
    x = 1,526,084.01/1,319.20
  6. Step 6: Final answer
    x = 1,156.83

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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.