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Finding the Fourth Proportional to 159.20, 239 and 78.12

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Solution

The fourth proportional to 159.20, 239 and 78.12 is: 117.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    159.20 : 239 = 78.12 : x
  2. Step 2: Convert to fraction form
    159.20/239 = 78.12/x
  3. Step 3: Cross multiply
    159.20x = 239 × 78.12
  4. Step 4: Simplify right side
    159.20x = 18,670.68
  5. Step 5: Solve for x
    x = 18,670.68/159.20
  6. Step 6: Final answer
    x = 117.28

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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.