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Finding the Fourth Proportional to 687.38, 1,029.45 and 378.77

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Solution

The fourth proportional to 687.38, 1,029.45 and 378.77 is: 567.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.38 : 1,029.45 = 378.77 : x
  2. Step 2: Convert to fraction form
    687.38/1,029.45 = 378.77/x
  3. Step 3: Cross multiply
    687.38x = 1,029.45 × 378.77
  4. Step 4: Simplify right side
    687.38x = 389,924.78
  5. Step 5: Solve for x
    x = 389,924.78/687.38
  6. Step 6: Final answer
    x = 567.26

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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.