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Finding the Fourth Proportional to 278.90, 418.32 and 156.78

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Solution

The fourth proportional to 278.90, 418.32 and 156.78 is: 235.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    278.90 : 418.32 = 156.78 : x
  2. Step 2: Convert to fraction form
    278.90/418.32 = 156.78/x
  3. Step 3: Cross multiply
    278.90x = 418.32 × 156.78
  4. Step 4: Simplify right side
    278.90x = 65,584.21
  5. Step 5: Solve for x
    x = 65,584.21/278.90
  6. Step 6: Final answer
    x = 235.15

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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.