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Finding the Fourth Proportional to 187.20, 258.38 and 129

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Solution

The fourth proportional to 187.20, 258.38 and 129 is: 178.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    187.20 : 258.38 = 129 : x
  2. Step 2: Convert to fraction form
    187.20/258.38 = 129/x
  3. Step 3: Cross multiply
    187.20x = 258.38 × 129
  4. Step 4: Simplify right side
    187.20x = 33,331.02
  5. Step 5: Solve for x
    x = 33,331.02/187.20
  6. Step 6: Final answer
    x = 178.05

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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.