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Finding the Fourth Proportional to 856.78, 1,285.57 and 423.93

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Solution

The fourth proportional to 856.78, 1,285.57 and 423.93 is: 636.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.78 : 1,285.57 = 423.93 : x
  2. Step 2: Convert to fraction form
    856.78/1,285.57 = 423.93/x
  3. Step 3: Cross multiply
    856.78x = 1,285.57 × 423.93
  4. Step 4: Simplify right side
    856.78x = 544,997.04
  5. Step 5: Solve for x
    x = 544,997.04/856.78
  6. Step 6: Final answer
    x = 636.10

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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.