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Finding the Fourth Proportional to 258.78, 388.29 and 121.74

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Solution

The fourth proportional to 258.78, 388.29 and 121.74 is: 182.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.78 : 388.29 = 121.74 : x
  2. Step 2: Convert to fraction form
    258.78/388.29 = 121.74/x
  3. Step 3: Cross multiply
    258.78x = 388.29 × 121.74
  4. Step 4: Simplify right side
    258.78x = 47,268.48
  5. Step 5: Solve for x
    x = 47,268.48/258.78
  6. Step 6: Final answer
    x = 182.66

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.