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Finding the Fourth Proportional to 153.85, 211.79 and 138.31

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Solution

The fourth proportional to 153.85, 211.79 and 138.31 is: 190.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    153.85 : 211.79 = 138.31 : x
  2. Step 2: Convert to fraction form
    153.85/211.79 = 138.31/x
  3. Step 3: Cross multiply
    153.85x = 211.79 × 138.31
  4. Step 4: Simplify right side
    153.85x = 29,292.10
  5. Step 5: Solve for x
    x = 29,292.10/153.85
  6. Step 6: Final answer
    x = 190.39

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.