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Finding the Fourth Proportional to 103.30, 142.62 and 81.40

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Solution

The fourth proportional to 103.30, 142.62 and 81.40 is: 112.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.30 : 142.62 = 81.40 : x
  2. Step 2: Convert to fraction form
    103.30/142.62 = 81.40/x
  3. Step 3: Cross multiply
    103.30x = 142.62 × 81.40
  4. Step 4: Simplify right side
    103.30x = 11,609.27
  5. Step 5: Solve for x
    x = 11,609.27/103.30
  6. Step 6: Final answer
    x = 112.38

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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.