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Finding the Fourth Proportional to 861.21, 1,291.68 and 276.19

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Solution

The fourth proportional to 861.21, 1,291.68 and 276.19 is: 414.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.21 : 1,291.68 = 276.19 : x
  2. Step 2: Convert to fraction form
    861.21/1,291.68 = 276.19/x
  3. Step 3: Cross multiply
    861.21x = 1,291.68 × 276.19
  4. Step 4: Simplify right side
    861.21x = 356,745.87
  5. Step 5: Solve for x
    x = 356,745.87/861.21
  6. Step 6: Final answer
    x = 414.24

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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.