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Finding the Fourth Proportional to 385.79, 578.91 and 142.49

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Solution

The fourth proportional to 385.79, 578.91 and 142.49 is: 213.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.79 : 578.91 = 142.49 : x
  2. Step 2: Convert to fraction form
    385.79/578.91 = 142.49/x
  3. Step 3: Cross multiply
    385.79x = 578.91 × 142.49
  4. Step 4: Simplify right side
    385.79x = 82,486.53
  5. Step 5: Solve for x
    x = 82,486.53/385.79
  6. Step 6: Final answer
    x = 213.81

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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.