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Finding the Fourth Proportional to 687.01, 1,025.54 and 640.90

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Solution

The fourth proportional to 687.01, 1,025.54 and 640.90 is: 956.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.01 : 1,025.54 = 640.90 : x
  2. Step 2: Convert to fraction form
    687.01/1,025.54 = 640.90/x
  3. Step 3: Cross multiply
    687.01x = 1,025.54 × 640.90
  4. Step 4: Simplify right side
    687.01x = 657,265.38
  5. Step 5: Solve for x
    x = 657,265.38/687.01
  6. Step 6: Final answer
    x = 956.71

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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.