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Finding the Fourth Proportional to 187.12, 258.10 and 128.89

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Solution

The fourth proportional to 187.12, 258.10 and 128.89 is: 177.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    187.12 : 258.10 = 128.89 : x
  2. Step 2: Convert to fraction form
    187.12/258.10 = 128.89/x
  3. Step 3: Cross multiply
    187.12x = 258.10 × 128.89
  4. Step 4: Simplify right side
    187.12x = 33,266.51
  5. Step 5: Solve for x
    x = 33,266.51/187.12
  6. Step 6: Final answer
    x = 177.78

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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.