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Finding the Fourth Proportional to 385.91, 578.53 and 138.96

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Solution

The fourth proportional to 385.91, 578.53 and 138.96 is: 208.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.91 : 578.53 = 138.96 : x
  2. Step 2: Convert to fraction form
    385.91/578.53 = 138.96/x
  3. Step 3: Cross multiply
    385.91x = 578.53 × 138.96
  4. Step 4: Simplify right side
    385.91x = 80,392.18
  5. Step 5: Solve for x
    x = 80,392.18/385.91
  6. Step 6: Final answer
    x = 208.32

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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.