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Finding the Fourth Proportional to 279.86, 419.78 and 115.40

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Solution

The fourth proportional to 279.86, 419.78 and 115.40 is: 173.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    279.86 : 419.78 = 115.40 : x
  2. Step 2: Convert to fraction form
    279.86/419.78 = 115.40/x
  3. Step 3: Cross multiply
    279.86x = 419.78 × 115.40
  4. Step 4: Simplify right side
    279.86x = 48,442.61
  5. Step 5: Solve for x
    x = 48,442.61/279.86
  6. Step 6: Final answer
    x = 173.10

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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.