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Finding the Fourth Proportional to 660.38, 911.33 and 398.45

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Solution

The fourth proportional to 660.38, 911.33 and 398.45 is: 549.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.38 : 911.33 = 398.45 : x
  2. Step 2: Convert to fraction form
    660.38/911.33 = 398.45/x
  3. Step 3: Cross multiply
    660.38x = 911.33 × 398.45
  4. Step 4: Simplify right side
    660.38x = 363,112.89
  5. Step 5: Solve for x
    x = 363,112.89/660.38
  6. Step 6: Final answer
    x = 549.86

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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.