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Finding the Fourth Proportional to 392.91, 586.31 and 390.65

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Solution

The fourth proportional to 392.91, 586.31 and 390.65 is: 582.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    392.91 : 586.31 = 390.65 : x
  2. Step 2: Convert to fraction form
    392.91/586.31 = 390.65/x
  3. Step 3: Cross multiply
    392.91x = 586.31 × 390.65
  4. Step 4: Simplify right side
    392.91x = 229,037.12
  5. Step 5: Solve for x
    x = 229,037.12/392.91
  6. Step 6: Final answer
    x = 582.93

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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.