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Finding the Fourth Proportional to 685.71, 945.84 and 405.84

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Solution

The fourth proportional to 685.71, 945.84 and 405.84 is: 559.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.71 : 945.84 = 405.84 : x
  2. Step 2: Convert to fraction form
    685.71/945.84 = 405.84/x
  3. Step 3: Cross multiply
    685.71x = 945.84 × 405.84
  4. Step 4: Simplify right side
    685.71x = 383,859.71
  5. Step 5: Solve for x
    x = 383,859.71/685.71
  6. Step 6: Final answer
    x = 559.80

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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.