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Finding the Fourth Proportional to 685.02, 945.29 and 390.31

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Solution

The fourth proportional to 685.02, 945.29 and 390.31 is: 538.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.02 : 945.29 = 390.31 : x
  2. Step 2: Convert to fraction form
    685.02/945.29 = 390.31/x
  3. Step 3: Cross multiply
    685.02x = 945.29 × 390.31
  4. Step 4: Simplify right side
    685.02x = 368,956.14
  5. Step 5: Solve for x
    x = 368,956.14/685.02
  6. Step 6: Final answer
    x = 538.61

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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.