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Finding the Fourth Proportional to 388.69, 583 and 128.85

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Solution

The fourth proportional to 388.69, 583 and 128.85 is: 193.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    388.69 : 583 = 128.85 : x
  2. Step 2: Convert to fraction form
    388.69/583 = 128.85/x
  3. Step 3: Cross multiply
    388.69x = 583 × 128.85
  4. Step 4: Simplify right side
    388.69x = 75,119.55
  5. Step 5: Solve for x
    x = 75,119.55/388.69
  6. Step 6: Final answer
    x = 193.26

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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.