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Finding the Fourth Proportional to 921.69, 1,382.81 and 394.79

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Solution

The fourth proportional to 921.69, 1,382.81 and 394.79 is: 592.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.69 : 1,382.81 = 394.79 : x
  2. Step 2: Convert to fraction form
    921.69/1,382.81 = 394.79/x
  3. Step 3: Cross multiply
    921.69x = 1,382.81 × 394.79
  4. Step 4: Simplify right side
    921.69x = 545,910.67
  5. Step 5: Solve for x
    x = 545,910.67/921.69
  6. Step 6: Final answer
    x = 592.29

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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.