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Finding the Fourth Proportional to 687.59, 1,031.38 and 415.43

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Solution

The fourth proportional to 687.59, 1,031.38 and 415.43 is: 623.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.59 : 1,031.38 = 415.43 : x
  2. Step 2: Convert to fraction form
    687.59/1,031.38 = 415.43/x
  3. Step 3: Cross multiply
    687.59x = 1,031.38 × 415.43
  4. Step 4: Simplify right side
    687.59x = 428,466.20
  5. Step 5: Solve for x
    x = 428,466.20/687.59
  6. Step 6: Final answer
    x = 623.14

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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.