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Finding the Fourth Proportional to 687.89, 1,031.13 and 427.07

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Solution

The fourth proportional to 687.89, 1,031.13 and 427.07 is: 640.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.89 : 1,031.13 = 427.07 : x
  2. Step 2: Convert to fraction form
    687.89/1,031.13 = 427.07/x
  3. Step 3: Cross multiply
    687.89x = 1,031.13 × 427.07
  4. Step 4: Simplify right side
    687.89x = 440,367.27
  5. Step 5: Solve for x
    x = 440,367.27/687.89
  6. Step 6: Final answer
    x = 640.17

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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.