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Finding the Fourth Proportional to 187.78, 258.96 and 138.77

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Solution

The fourth proportional to 187.78, 258.96 and 138.77 is: 191.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    187.78 : 258.96 = 138.77 : x
  2. Step 2: Convert to fraction form
    187.78/258.96 = 138.77/x
  3. Step 3: Cross multiply
    187.78x = 258.96 × 138.77
  4. Step 4: Simplify right side
    187.78x = 35,935.88
  5. Step 5: Solve for x
    x = 35,935.88/187.78
  6. Step 6: Final answer
    x = 191.37

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.