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Finding the Fourth Proportional to 385.99, 578.99 and 139.14

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Solution

The fourth proportional to 385.99, 578.99 and 139.14 is: 208.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    385.99 : 578.99 = 139.14 : x
  2. Step 2: Convert to fraction form
    385.99/578.99 = 139.14/x
  3. Step 3: Cross multiply
    385.99x = 578.99 × 139.14
  4. Step 4: Simplify right side
    385.99x = 80,560.67
  5. Step 5: Solve for x
    x = 80,560.67/385.99
  6. Step 6: Final answer
    x = 208.71

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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.