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Finding the Fourth Proportional to 854.21, 1,280.91 and 391.85

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Solution

The fourth proportional to 854.21, 1,280.91 and 391.85 is: 587.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    854.21 : 1,280.91 = 391.85 : x
  2. Step 2: Convert to fraction form
    854.21/1,280.91 = 391.85/x
  3. Step 3: Cross multiply
    854.21x = 1,280.91 × 391.85
  4. Step 4: Simplify right side
    854.21x = 501,924.58
  5. Step 5: Solve for x
    x = 501,924.58/854.21
  6. Step 6: Final answer
    x = 587.59

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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.