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Finding the Fourth Proportional to 102.72, 142.31 and 100.22

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Solution

The fourth proportional to 102.72, 142.31 and 100.22 is: 138.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    102.72 : 142.31 = 100.22 : x
  2. Step 2: Convert to fraction form
    102.72/142.31 = 100.22/x
  3. Step 3: Cross multiply
    102.72x = 142.31 × 100.22
  4. Step 4: Simplify right side
    102.72x = 14,261.85
  5. Step 5: Solve for x
    x = 14,261.85/102.72
  6. Step 6: Final answer
    x = 138.84

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.