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Finding the Fourth Proportional to 103.12, 142.34 and 61.69

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Solution

The fourth proportional to 103.12, 142.34 and 61.69 is: 85.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.12 : 142.34 = 61.69 : x
  2. Step 2: Convert to fraction form
    103.12/142.34 = 61.69/x
  3. Step 3: Cross multiply
    103.12x = 142.34 × 61.69
  4. Step 4: Simplify right side
    103.12x = 8,780.95
  5. Step 5: Solve for x
    x = 8,780.95/103.12
  6. Step 6: Final answer
    x = 85.15

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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.