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Finding the Fourth Proportional to 687.31, 1,031.08 and 415.07

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Solution

The fourth proportional to 687.31, 1,031.08 and 415.07 is: 622.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.31 : 1,031.08 = 415.07 : x
  2. Step 2: Convert to fraction form
    687.31/1,031.08 = 415.07/x
  3. Step 3: Cross multiply
    687.31x = 1,031.08 × 415.07
  4. Step 4: Simplify right side
    687.31x = 427,974.63
  5. Step 5: Solve for x
    x = 427,974.63/687.31
  6. Step 6: Final answer
    x = 622.68

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.