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Finding the Fourth Proportional to 278.94, 418.41 and 86.57

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Solution

The fourth proportional to 278.94, 418.41 and 86.57 is: 129.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    278.94 : 418.41 = 86.57 : x
  2. Step 2: Convert to fraction form
    278.94/418.41 = 86.57/x
  3. Step 3: Cross multiply
    278.94x = 418.41 × 86.57
  4. Step 4: Simplify right side
    278.94x = 36,219.23
  5. Step 5: Solve for x
    x = 36,219.23/278.94
  6. Step 6: Final answer
    x = 129.85

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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.