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Finding the Fourth Proportional to 687.78, 949.31 and 425.64

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Solution

The fourth proportional to 687.78, 949.31 and 425.64 is: 587.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.78 : 949.31 = 425.64 : x
  2. Step 2: Convert to fraction form
    687.78/949.31 = 425.64/x
  3. Step 3: Cross multiply
    687.78x = 949.31 × 425.64
  4. Step 4: Simplify right side
    687.78x = 404,064.31
  5. Step 5: Solve for x
    x = 404,064.31/687.78
  6. Step 6: Final answer
    x = 587.49

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.