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Finding the Fourth Proportional to 388.81, 582.80 and 128.74

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Solution

The fourth proportional to 388.81, 582.80 and 128.74 is: 192.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    388.81 : 582.80 = 128.74 : x
  2. Step 2: Convert to fraction form
    388.81/582.80 = 128.74/x
  3. Step 3: Cross multiply
    388.81x = 582.80 × 128.74
  4. Step 4: Simplify right side
    388.81x = 75,027.57
  5. Step 5: Solve for x
    x = 75,027.57/388.81
  6. Step 6: Final answer
    x = 192.97

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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.