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Finding the Fourth Proportional to 389.31, 583.40 and 206.85

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Solution

The fourth proportional to 389.31, 583.40 and 206.85 is: 309.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.31 : 583.40 = 206.85 : x
  2. Step 2: Convert to fraction form
    389.31/583.40 = 206.85/x
  3. Step 3: Cross multiply
    389.31x = 583.40 × 206.85
  4. Step 4: Simplify right side
    389.31x = 120,678.99
  5. Step 5: Solve for x
    x = 120,678.99/389.31
  6. Step 6: Final answer
    x = 309.98

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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.