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Finding the Fourth Proportional to 386.78, 533.57 and 281.70

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Solution

The fourth proportional to 386.78, 533.57 and 281.70 is: 388.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.78 : 533.57 = 281.70 : x
  2. Step 2: Convert to fraction form
    386.78/533.57 = 281.70/x
  3. Step 3: Cross multiply
    386.78x = 533.57 × 281.70
  4. Step 4: Simplify right side
    386.78x = 150,305.26
  5. Step 5: Solve for x
    x = 150,305.26/386.78
  6. Step 6: Final answer
    x = 388.61

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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.