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Finding the Fourth Proportional to 406.68, 561.78 and 391.70

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Solution

The fourth proportional to 406.68, 561.78 and 391.70 is: 541.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    406.68 : 561.78 = 391.70 : x
  2. Step 2: Convert to fraction form
    406.68/561.78 = 391.70/x
  3. Step 3: Cross multiply
    406.68x = 561.78 × 391.70
  4. Step 4: Simplify right side
    406.68x = 220,049.23
  5. Step 5: Solve for x
    x = 220,049.23/406.68
  6. Step 6: Final answer
    x = 541.09

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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.