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Finding the Fourth Proportional to 685.11, 945.32 and 405.56

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Solution

The fourth proportional to 685.11, 945.32 and 405.56 is: 559.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.11 : 945.32 = 405.56 : x
  2. Step 2: Convert to fraction form
    685.11/945.32 = 405.56/x
  3. Step 3: Cross multiply
    685.11x = 945.32 × 405.56
  4. Step 4: Simplify right side
    685.11x = 383,381.28
  5. Step 5: Solve for x
    x = 383,381.28/685.11
  6. Step 6: Final answer
    x = 559.59

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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.