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Finding the Third Proportional to 642.75 and 1,285.50

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Solution

The third proportional to 642.75 and 1,285.50 is: 2,571

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.75 : 1,285.50 = 1,285.50 : x
  2. Step 2: Convert to fraction form
    642.75/1,285.50 = 1,285.50/x
  3. Step 3: Cross multiply
    642.75x = 1,285.50 × 1,285.50
  4. Step 4: Simplify right side
    642.75x = 1,652,510.25
  5. Step 5: Solve for x
    x = 1,652,510.25/642.75
  6. Step 6: Final answer
    x = 2,571

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Why These Related Problems?

These problems maintain the same ratio (2) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.