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Finding the Fourth Proportional to 854.56, 1,280.94 and 420.82

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Solution

The fourth proportional to 854.56, 1,280.94 and 420.82 is: 630.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    854.56 : 1,280.94 = 420.82 : x
  2. Step 2: Convert to fraction form
    854.56/1,280.94 = 420.82/x
  3. Step 3: Cross multiply
    854.56x = 1,280.94 × 420.82
  4. Step 4: Simplify right side
    854.56x = 539,045.17
  5. Step 5: Solve for x
    x = 539,045.17/854.56
  6. Step 6: Final answer
    x = 630.79

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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.