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Finding the Fourth Proportional to 685.85, 1,027.72 and 407.64

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Solution

The fourth proportional to 685.85, 1,027.72 and 407.64 is: 610.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.85 : 1,027.72 = 407.64 : x
  2. Step 2: Convert to fraction form
    685.85/1,027.72 = 407.64/x
  3. Step 3: Cross multiply
    685.85x = 1,027.72 × 407.64
  4. Step 4: Simplify right side
    685.85x = 418,944.14
  5. Step 5: Solve for x
    x = 418,944.14/685.85
  6. Step 6: Final answer
    x = 610.84

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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.