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Finding the Fourth Proportional to 857.76, 1,285.51 and 388.89

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Solution

The fourth proportional to 857.76, 1,285.51 and 388.89 is: 582.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    857.76 : 1,285.51 = 388.89 : x
  2. Step 2: Convert to fraction form
    857.76/1,285.51 = 388.89/x
  3. Step 3: Cross multiply
    857.76x = 1,285.51 × 388.89
  4. Step 4: Simplify right side
    857.76x = 499,921.98
  5. Step 5: Solve for x
    x = 499,921.98/857.76
  6. Step 6: Final answer
    x = 582.82

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.