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Finding the Fourth Proportional to 187.20, 258.25 and 121.69

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Solution

The fourth proportional to 187.20, 258.25 and 121.69 is: 167.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    187.20 : 258.25 = 121.69 : x
  2. Step 2: Convert to fraction form
    187.20/258.25 = 121.69/x
  3. Step 3: Cross multiply
    187.20x = 258.25 × 121.69
  4. Step 4: Simplify right side
    187.20x = 31,426.44
  5. Step 5: Solve for x
    x = 31,426.44/187.20
  6. Step 6: Final answer
    x = 167.88

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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.