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Finding the Fourth Proportional to 858.42, 1,287.78 and 371.82

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Solution

The fourth proportional to 858.42, 1,287.78 and 371.82 is: 557.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    858.42 : 1,287.78 = 371.82 : x
  2. Step 2: Convert to fraction form
    858.42/1,287.78 = 371.82/x
  3. Step 3: Cross multiply
    858.42x = 1,287.78 × 371.82
  4. Step 4: Simplify right side
    858.42x = 478,822.36
  5. Step 5: Solve for x
    x = 478,822.36/858.42
  6. Step 6: Final answer
    x = 557.79

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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.