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Finding the Fourth Proportional to 660.85, 911.98 and 398.81

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Solution

The fourth proportional to 660.85, 911.98 and 398.81 is: 550.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.85 : 911.98 = 398.81 : x
  2. Step 2: Convert to fraction form
    660.85/911.98 = 398.81/x
  3. Step 3: Cross multiply
    660.85x = 911.98 × 398.81
  4. Step 4: Simplify right side
    660.85x = 363,708.03
  5. Step 5: Solve for x
    x = 363,708.03/660.85
  6. Step 6: Final answer
    x = 550.37

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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.