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Finding the Fourth Proportional to 406.91, 561.33 and 391.19

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Solution

The fourth proportional to 406.91, 561.33 and 391.19 is: 539.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    406.91 : 561.33 = 391.19 : x
  2. Step 2: Convert to fraction form
    406.91/561.33 = 391.19/x
  3. Step 3: Cross multiply
    406.91x = 561.33 × 391.19
  4. Step 4: Simplify right side
    406.91x = 219,586.68
  5. Step 5: Solve for x
    x = 219,586.68/406.91
  6. Step 6: Final answer
    x = 539.64

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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.