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Finding the Fourth Proportional to 187.39, 258.51 and 121.87

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Solution

The fourth proportional to 187.39, 258.51 and 121.87 is: 168.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    187.39 : 258.51 = 121.87 : x
  2. Step 2: Convert to fraction form
    187.39/258.51 = 121.87/x
  3. Step 3: Cross multiply
    187.39x = 258.51 × 121.87
  4. Step 4: Simplify right side
    187.39x = 31,504.61
  5. Step 5: Solve for x
    x = 31,504.61/187.39
  6. Step 6: Final answer
    x = 168.12

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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.