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Finding the Fourth Proportional to 187.29, 258.45 and 121.90

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Solution

The fourth proportional to 187.29, 258.45 and 121.90 is: 168.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    187.29 : 258.45 = 121.90 : x
  2. Step 2: Convert to fraction form
    187.29/258.45 = 121.90/x
  3. Step 3: Cross multiply
    187.29x = 258.45 × 121.90
  4. Step 4: Simplify right side
    187.29x = 31,505.06
  5. Step 5: Solve for x
    x = 31,505.06/187.29
  6. Step 6: Final answer
    x = 168.22

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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.