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Finding the Third Proportional to 387.50 and 489.50

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Solution

The third proportional to 387.50 and 489.50 is: 618.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.50 : 489.50 = 489.50 : x
  2. Step 2: Convert to fraction form
    387.50/489.50 = 489.50/x
  3. Step 3: Cross multiply
    387.50x = 489.50 × 489.50
  4. Step 4: Simplify right side
    387.50x = 239,610.25
  5. Step 5: Solve for x
    x = 239,610.25/387.50
  6. Step 6: Final answer
    x = 618.35

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Why These Related Problems?

These problems maintain the same ratio (1.26) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.