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Finding the Fourth Proportional to 660.49, 911.64 and 398.68

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Solution

The fourth proportional to 660.49, 911.64 and 398.68 is: 550.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    660.49 : 911.64 = 398.68 : x
  2. Step 2: Convert to fraction form
    660.49/911.64 = 398.68/x
  3. Step 3: Cross multiply
    660.49x = 911.64 × 398.68
  4. Step 4: Simplify right side
    660.49x = 363,452.64
  5. Step 5: Solve for x
    x = 363,452.64/660.49
  6. Step 6: Final answer
    x = 550.28

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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.