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Finding the Fourth Proportional to 258.53, 387.95 and 128.57

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Solution

The fourth proportional to 258.53, 387.95 and 128.57 is: 192.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    258.53 : 387.95 = 128.57 : x
  2. Step 2: Convert to fraction form
    258.53/387.95 = 128.57/x
  3. Step 3: Cross multiply
    258.53x = 387.95 × 128.57
  4. Step 4: Simplify right side
    258.53x = 49,876.15
  5. Step 5: Solve for x
    x = 49,876.15/258.53
  6. Step 6: Final answer
    x = 192.93

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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.