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Finding the Fourth Proportional to 687.02, 1,029.81 and 393.87

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Solution

The fourth proportional to 687.02, 1,029.81 and 393.87 is: 590.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    687.02 : 1,029.81 = 393.87 : x
  2. Step 2: Convert to fraction form
    687.02/1,029.81 = 393.87/x
  3. Step 3: Cross multiply
    687.02x = 1,029.81 × 393.87
  4. Step 4: Simplify right side
    687.02x = 405,611.26
  5. Step 5: Solve for x
    x = 405,611.26/687.02
  6. Step 6: Final answer
    x = 590.39

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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.