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Finding the Third Proportional to 643.31 and 688.88

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Solution

The third proportional to 643.31 and 688.88 is: 737.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    643.31 : 688.88 = 688.88 : x
  2. Step 2: Convert to fraction form
    643.31/688.88 = 688.88/x
  3. Step 3: Cross multiply
    643.31x = 688.88 × 688.88
  4. Step 4: Simplify right side
    643.31x = 474,548.77
  5. Step 5: Solve for x
    x = 474,548.77/643.31
  6. Step 6: Final answer
    x = 737.66

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Why These Related Problems?

These problems maintain the same ratio (1.07) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.