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Finding the Fourth Proportional to 861.77, 1,291.27 and 779.76

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Solution

The fourth proportional to 861.77, 1,291.27 and 779.76 is: 1,168.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.77 : 1,291.27 = 779.76 : x
  2. Step 2: Convert to fraction form
    861.77/1,291.27 = 779.76/x
  3. Step 3: Cross multiply
    861.77x = 1,291.27 × 779.76
  4. Step 4: Simplify right side
    861.77x = 1,006,880.70
  5. Step 5: Solve for x
    x = 1,006,880.70/861.77
  6. Step 6: Final answer
    x = 1,168.39

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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.