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Finding the Fourth Proportional to 861.15, 1,291.80 and 276.21

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Solution

The fourth proportional to 861.15, 1,291.80 and 276.21 is: 414.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    861.15 : 1,291.80 = 276.21 : x
  2. Step 2: Convert to fraction form
    861.15/1,291.80 = 276.21/x
  3. Step 3: Cross multiply
    861.15x = 1,291.80 × 276.21
  4. Step 4: Simplify right side
    861.15x = 356,808.08
  5. Step 5: Solve for x
    x = 356,808.08/861.15
  6. Step 6: Final answer
    x = 414.34

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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.