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Finding the Fourth Proportional to 856.90, 1,285.37 and 308.80

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Solution

The fourth proportional to 856.90, 1,285.37 and 308.80 is: 463.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.90 : 1,285.37 = 308.80 : x
  2. Step 2: Convert to fraction form
    856.90/1,285.37 = 308.80/x
  3. Step 3: Cross multiply
    856.90x = 1,285.37 × 308.80
  4. Step 4: Simplify right side
    856.90x = 396,920.71
  5. Step 5: Solve for x
    x = 396,920.71/856.90
  6. Step 6: Final answer
    x = 463.21

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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.