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Finding the Fourth Proportional to 278.80, 417.90 and 105.40

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Solution

The fourth proportional to 278.80, 417.90 and 105.40 is: 157.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    278.80 : 417.90 = 105.40 : x
  2. Step 2: Convert to fraction form
    278.80/417.90 = 105.40/x
  3. Step 3: Cross multiply
    278.80x = 417.90 × 105.40
  4. Step 4: Simplify right side
    278.80x = 44,046.66
  5. Step 5: Solve for x
    x = 44,046.66/278.80
  6. Step 6: Final answer
    x = 157.99

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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.