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Finding the Fourth Proportional to 1,280.86, 1,921.83 and 761.85

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Solution

The fourth proportional to 1,280.86, 1,921.83 and 761.85 is: 1,143.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,280.86 : 1,921.83 = 761.85 : x
  2. Step 2: Convert to fraction form
    1,280.86/1,921.83 = 761.85/x
  3. Step 3: Cross multiply
    1,280.86x = 1,921.83 × 761.85
  4. Step 4: Simplify right side
    1,280.86x = 1,464,146.19
  5. Step 5: Solve for x
    x = 1,464,146.19/1,280.86
  6. Step 6: Final answer
    x = 1,143.10

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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.