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Finding the Fourth Proportional to 2,808.78, 4,213.04 and 861

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Solution

The fourth proportional to 2,808.78, 4,213.04 and 861 is: 1,291.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,808.78 : 4,213.04 = 861 : x
  2. Step 2: Convert to fraction form
    2,808.78/4,213.04 = 861/x
  3. Step 3: Cross multiply
    2,808.78x = 4,213.04 × 861
  4. Step 4: Simplify right side
    2,808.78x = 3,627,427.44
  5. Step 5: Solve for x
    x = 3,627,427.44/2,808.78
  6. Step 6: Final answer
    x = 1,291.46

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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.