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Finding the Fourth Proportional to 258.60, 387.63 and 128.46

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Solution

The fourth proportional to 258.60, 387.63 and 128.46 is: 192.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.60 : 387.63 = 128.46 : x
  2. Step 2: Convert to fraction form
    258.60/387.63 = 128.46/x
  3. Step 3: Cross multiply
    258.60x = 387.63 × 128.46
  4. Step 4: Simplify right side
    258.60x = 49,794.95
  5. Step 5: Solve for x
    x = 49,794.95/258.60
  6. Step 6: Final answer
    x = 192.56

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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.