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Finding the Third Proportional to 400.31 and 642.19

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Solution

The third proportional to 400.31 and 642.19 is: 1,030.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    400.31 : 642.19 = 642.19 : x
  2. Step 2: Convert to fraction form
    400.31/642.19 = 642.19/x
  3. Step 3: Cross multiply
    400.31x = 642.19 × 642.19
  4. Step 4: Simplify right side
    400.31x = 412,404.79
  5. Step 5: Solve for x
    x = 412,404.79/400.31
  6. Step 6: Final answer
    x = 1,030.21

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Why These Related Problems?

These problems maintain the same ratio (1.60) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.