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Finding the Fourth Proportional to 391.78, 584.77 and 345.65

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Solution

The fourth proportional to 391.78, 584.77 and 345.65 is: 515.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    391.78 : 584.77 = 345.65 : x
  2. Step 2: Convert to fraction form
    391.78/584.77 = 345.65/x
  3. Step 3: Cross multiply
    391.78x = 584.77 × 345.65
  4. Step 4: Simplify right side
    391.78x = 202,124.02
  5. Step 5: Solve for x
    x = 202,124.02/391.78
  6. Step 6: Final answer
    x = 515.92

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.