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Finding the Fourth Proportional to 861.82, 1,291.91 and 785.75

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Solution

The fourth proportional to 861.82, 1,291.91 and 785.75 is: 1,177.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.82 : 1,291.91 = 785.75 : x
  2. Step 2: Convert to fraction form
    861.82/1,291.91 = 785.75/x
  3. Step 3: Cross multiply
    861.82x = 1,291.91 × 785.75
  4. Step 4: Simplify right side
    861.82x = 1,015,107.89
  5. Step 5: Solve for x
    x = 1,015,107.89/861.82
  6. Step 6: Final answer
    x = 1,177.87

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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.