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Finding the Fourth Proportional to 856.78, 1,285.70 and 394.62

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Solution

The fourth proportional to 856.78, 1,285.70 and 394.62 is: 592.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.78 : 1,285.70 = 394.62 : x
  2. Step 2: Convert to fraction form
    856.78/1,285.70 = 394.62/x
  3. Step 3: Cross multiply
    856.78x = 1,285.70 × 394.62
  4. Step 4: Simplify right side
    856.78x = 507,364.48
  5. Step 5: Solve for x
    x = 507,364.48/856.78
  6. Step 6: Final answer
    x = 592.18

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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.