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Finding the Fourth Proportional to 386.05, 578.98 and 142.55

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Solution

The fourth proportional to 386.05, 578.98 and 142.55 is: 213.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    386.05 : 578.98 = 142.55 : x
  2. Step 2: Convert to fraction form
    386.05/578.98 = 142.55/x
  3. Step 3: Cross multiply
    386.05x = 578.98 × 142.55
  4. Step 4: Simplify right side
    386.05x = 82,533.60
  5. Step 5: Solve for x
    x = 82,533.60/386.05
  6. Step 6: Final answer
    x = 213.79

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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.