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Finding the Fourth Proportional to 687.57, 947.91 and 490.74

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Solution

The fourth proportional to 687.57, 947.91 and 490.74 is: 676.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.57 : 947.91 = 490.74 : x
  2. Step 2: Convert to fraction form
    687.57/947.91 = 490.74/x
  3. Step 3: Cross multiply
    687.57x = 947.91 × 490.74
  4. Step 4: Simplify right side
    687.57x = 465,177.35
  5. Step 5: Solve for x
    x = 465,177.35/687.57
  6. Step 6: Final answer
    x = 676.55

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.