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Finding the Fourth Proportional to 309.78, 464.03 and 138.90

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Solution

The fourth proportional to 309.78, 464.03 and 138.90 is: 208.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.78 : 464.03 = 138.90 : x
  2. Step 2: Convert to fraction form
    309.78/464.03 = 138.90/x
  3. Step 3: Cross multiply
    309.78x = 464.03 × 138.90
  4. Step 4: Simplify right side
    309.78x = 64,453.77
  5. Step 5: Solve for x
    x = 64,453.77/309.78
  6. Step 6: Final answer
    x = 208.06

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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.