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Finding the Fourth Proportional to 685.32, 1,029.06 and 393.72

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Solution

The fourth proportional to 685.32, 1,029.06 and 393.72 is: 591.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    685.32 : 1,029.06 = 393.72 : x
  2. Step 2: Convert to fraction form
    685.32/1,029.06 = 393.72/x
  3. Step 3: Cross multiply
    685.32x = 1,029.06 × 393.72
  4. Step 4: Simplify right side
    685.32x = 405,161.50
  5. Step 5: Solve for x
    x = 405,161.50/685.32
  6. Step 6: Final answer
    x = 591.20

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.