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Finding the Fourth Proportional to 388.54, 582.85 and 128.71

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Solution

The fourth proportional to 388.54, 582.85 and 128.71 is: 193.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    388.54 : 582.85 = 128.71 : x
  2. Step 2: Convert to fraction form
    388.54/582.85 = 128.71/x
  3. Step 3: Cross multiply
    388.54x = 582.85 × 128.71
  4. Step 4: Simplify right side
    388.54x = 75,019.51
  5. Step 5: Solve for x
    x = 75,019.51/388.54
  6. Step 6: Final answer
    x = 193.08

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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.