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Finding the Fourth Proportional to 1,917.86, 2,877.31 and 685.40

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Solution

The fourth proportional to 1,917.86, 2,877.31 and 685.40 is: 1,028.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,917.86 : 2,877.31 = 685.40 : x
  2. Step 2: Convert to fraction form
    1,917.86/2,877.31 = 685.40/x
  3. Step 3: Cross multiply
    1,917.86x = 2,877.31 × 685.40
  4. Step 4: Simplify right side
    1,917.86x = 1,972,094.74
  5. Step 5: Solve for x
    x = 1,972,094.74/1,917.86
  6. Step 6: Final answer
    x = 1,028.28

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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.