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Finding the Fourth Proportional to 406.98, 561.84 and 391.20

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Solution

The fourth proportional to 406.98, 561.84 and 391.20 is: 540.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    406.98 : 561.84 = 391.20 : x
  2. Step 2: Convert to fraction form
    406.98/561.84 = 391.20/x
  3. Step 3: Cross multiply
    406.98x = 561.84 × 391.20
  4. Step 4: Simplify right side
    406.98x = 219,791.81
  5. Step 5: Solve for x
    x = 219,791.81/406.98
  6. Step 6: Final answer
    x = 540.06

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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.