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Finding the Fourth Proportional to 687, 1,023.97 and 664.50

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Solution

The fourth proportional to 687, 1,023.97 and 664.50 is: 990.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    687 : 1,023.97 = 664.50 : x
  2. Step 2: Convert to fraction form
    687/1,023.97 = 664.50/x
  3. Step 3: Cross multiply
    687x = 1,023.97 × 664.50
  4. Step 4: Simplify right side
    687x = 680,428.07
  5. Step 5: Solve for x
    x = 680,428.07/687
  6. Step 6: Final answer
    x = 990.43

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.