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Finding the Fourth Proportional to 685.57, 945.99 and 390.88

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Solution

The fourth proportional to 685.57, 945.99 and 390.88 is: 539.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.57 : 945.99 = 390.88 : x
  2. Step 2: Convert to fraction form
    685.57/945.99 = 390.88/x
  3. Step 3: Cross multiply
    685.57x = 945.99 × 390.88
  4. Step 4: Simplify right side
    685.57x = 369,768.57
  5. Step 5: Solve for x
    x = 369,768.57/685.57
  6. Step 6: Final answer
    x = 539.36

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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.