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Finding the Fourth Proportional to 856.70, 1,285.05 and 764.90

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Solution

The fourth proportional to 856.70, 1,285.05 and 764.90 is: 1,147.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.70 : 1,285.05 = 764.90 : x
  2. Step 2: Convert to fraction form
    856.70/1,285.05 = 764.90/x
  3. Step 3: Cross multiply
    856.70x = 1,285.05 × 764.90
  4. Step 4: Simplify right side
    856.70x = 982,934.75
  5. Step 5: Solve for x
    x = 982,934.75/856.70
  6. Step 6: Final answer
    x = 1,147.35

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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.