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Finding the Fourth Proportional to 685.60, 945.74 and 405.70

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Solution

The fourth proportional to 685.60, 945.74 and 405.70 is: 559.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.60 : 945.74 = 405.70 : x
  2. Step 2: Convert to fraction form
    685.60/945.74 = 405.70/x
  3. Step 3: Cross multiply
    685.60x = 945.74 × 405.70
  4. Step 4: Simplify right side
    685.60x = 383,686.72
  5. Step 5: Solve for x
    x = 383,686.72/685.60
  6. Step 6: Final answer
    x = 559.64

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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.