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Finding the Fourth Proportional to 687.86, 1,031.91 and 341.21

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Solution

The fourth proportional to 687.86, 1,031.91 and 341.21 is: 511.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.86 : 1,031.91 = 341.21 : x
  2. Step 2: Convert to fraction form
    687.86/1,031.91 = 341.21/x
  3. Step 3: Cross multiply
    687.86x = 1,031.91 × 341.21
  4. Step 4: Simplify right side
    687.86x = 352,099.31
  5. Step 5: Solve for x
    x = 352,099.31/687.86
  6. Step 6: Final answer
    x = 511.88

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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.