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Finding the Fourth Proportional to 1,920.78, 2,881.17 and 1,272.78

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Solution

The fourth proportional to 1,920.78, 2,881.17 and 1,272.78 is: 1,909.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,920.78 : 2,881.17 = 1,272.78 : x
  2. Step 2: Convert to fraction form
    1,920.78/2,881.17 = 1,272.78/x
  3. Step 3: Cross multiply
    1,920.78x = 2,881.17 × 1,272.78
  4. Step 4: Simplify right side
    1,920.78x = 3,667,095.55
  5. Step 5: Solve for x
    x = 3,667,095.55/1,920.78
  6. Step 6: Final answer
    x = 1,909.17

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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.