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Finding the Fourth Proportional to 689.78, 1,035.23 and 393.48

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Solution

The fourth proportional to 689.78, 1,035.23 and 393.48 is: 590.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    689.78 : 1,035.23 = 393.48 : x
  2. Step 2: Convert to fraction form
    689.78/1,035.23 = 393.48/x
  3. Step 3: Cross multiply
    689.78x = 1,035.23 × 393.48
  4. Step 4: Simplify right side
    689.78x = 407,342.30
  5. Step 5: Solve for x
    x = 407,342.30/689.78
  6. Step 6: Final answer
    x = 590.54

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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.