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Finding the Fourth Proportional to 388.39, 582.61 and 128.42

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Solution

The fourth proportional to 388.39, 582.61 and 128.42 is: 192.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    388.39 : 582.61 = 128.42 : x
  2. Step 2: Convert to fraction form
    388.39/582.61 = 128.42/x
  3. Step 3: Cross multiply
    388.39x = 582.61 × 128.42
  4. Step 4: Simplify right side
    388.39x = 74,816.88
  5. Step 5: Solve for x
    x = 74,816.88/388.39
  6. Step 6: Final answer
    x = 192.63

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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.