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Finding the Fourth Proportional to 159.78, 239.76 and 91.38

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Solution

The fourth proportional to 159.78, 239.76 and 91.38 is: 137.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    159.78 : 239.76 = 91.38 : x
  2. Step 2: Convert to fraction form
    159.78/239.76 = 91.38/x
  3. Step 3: Cross multiply
    159.78x = 239.76 × 91.38
  4. Step 4: Simplify right side
    159.78x = 21,909.27
  5. Step 5: Solve for x
    x = 21,909.27/159.78
  6. Step 6: Final answer
    x = 137.12

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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.