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Finding the Fourth Proportional to 103.15, 142.27 and 61.70

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Solution

The fourth proportional to 103.15, 142.27 and 61.70 is: 85.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.15 : 142.27 = 61.70 : x
  2. Step 2: Convert to fraction form
    103.15/142.27 = 61.70/x
  3. Step 3: Cross multiply
    103.15x = 142.27 × 61.70
  4. Step 4: Simplify right side
    103.15x = 8,778.06
  5. Step 5: Solve for x
    x = 8,778.06/103.15
  6. Step 6: Final answer
    x = 85.10

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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.