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Finding the Fourth Proportional to 385.81, 578.71 and 111.90

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Solution

The fourth proportional to 385.81, 578.71 and 111.90 is: 167.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.81 : 578.71 = 111.90 : x
  2. Step 2: Convert to fraction form
    385.81/578.71 = 111.90/x
  3. Step 3: Cross multiply
    385.81x = 578.71 × 111.90
  4. Step 4: Simplify right side
    385.81x = 64,757.65
  5. Step 5: Solve for x
    x = 64,757.65/385.81
  6. Step 6: Final answer
    x = 167.85

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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.