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Finding the Third Proportional to 688.50 and 840.38

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Solution

The third proportional to 688.50 and 840.38 is: 1,025.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    688.50 : 840.38 = 840.38 : x
  2. Step 2: Convert to fraction form
    688.50/840.38 = 840.38/x
  3. Step 3: Cross multiply
    688.50x = 840.38 × 840.38
  4. Step 4: Simplify right side
    688.50x = 706,230.14
  5. Step 5: Solve for x
    x = 706,230.14/688.50
  6. Step 6: Final answer
    x = 1,025.75

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Why These Related Problems?

These problems maintain the same ratio (1.22) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.