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Finding the Fourth Proportional to 388.28, 582.42 and 99.72

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Solution

The fourth proportional to 388.28, 582.42 and 99.72 is: 149.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    388.28 : 582.42 = 99.72 : x
  2. Step 2: Convert to fraction form
    388.28/582.42 = 99.72/x
  3. Step 3: Cross multiply
    388.28x = 582.42 × 99.72
  4. Step 4: Simplify right side
    388.28x = 58,078.92
  5. Step 5: Solve for x
    x = 58,078.92/388.28
  6. Step 6: Final answer
    x = 149.58

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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.