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Finding the Fourth Proportional to 645.78, 891.23 and 383.93

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Solution

The fourth proportional to 645.78, 891.23 and 383.93 is: 529.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    645.78 : 891.23 = 383.93 : x
  2. Step 2: Convert to fraction form
    645.78/891.23 = 383.93/x
  3. Step 3: Cross multiply
    645.78x = 891.23 × 383.93
  4. Step 4: Simplify right side
    645.78x = 342,163.56
  5. Step 5: Solve for x
    x = 342,163.56/645.78
  6. Step 6: Final answer
    x = 529.85

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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.