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Finding the Fourth Proportional to 258.34, 387.53 and 128.47

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Solution

The fourth proportional to 258.34, 387.53 and 128.47 is: 192.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.34 : 387.53 = 128.47 : x
  2. Step 2: Convert to fraction form
    258.34/387.53 = 128.47/x
  3. Step 3: Cross multiply
    258.34x = 387.53 × 128.47
  4. Step 4: Simplify right side
    258.34x = 49,783.40
  5. Step 5: Solve for x
    x = 49,783.40/258.34
  6. Step 6: Final answer
    x = 192.71

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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.