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Finding the Fourth Proportional to 666.54, 919.78 and 386.85

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Solution

The fourth proportional to 666.54, 919.78 and 386.85 is: 533.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    666.54 : 919.78 = 386.85 : x
  2. Step 2: Convert to fraction form
    666.54/919.78 = 386.85/x
  3. Step 3: Cross multiply
    666.54x = 919.78 × 386.85
  4. Step 4: Simplify right side
    666.54x = 355,815.93
  5. Step 5: Solve for x
    x = 355,815.93/666.54
  6. Step 6: Final answer
    x = 533.83

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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.