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Finding the Third Proportional to 390.94 and 840.56

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Solution

The third proportional to 390.94 and 840.56 is: 1,807.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.94 : 840.56 = 840.56 : x
  2. Step 2: Convert to fraction form
    390.94/840.56 = 840.56/x
  3. Step 3: Cross multiply
    390.94x = 840.56 × 840.56
  4. Step 4: Simplify right side
    390.94x = 706,545.32
  5. Step 5: Solve for x
    x = 706,545.32/390.94
  6. Step 6: Final answer
    x = 1,807.31

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Why These Related Problems?

These problems maintain the same ratio (2.15) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.