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Finding the Fourth Proportional to 103.49, 142.74 and 86.09

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Solution

The fourth proportional to 103.49, 142.74 and 86.09 is: 118.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.49 : 142.74 = 86.09 : x
  2. Step 2: Convert to fraction form
    103.49/142.74 = 86.09/x
  3. Step 3: Cross multiply
    103.49x = 142.74 × 86.09
  4. Step 4: Simplify right side
    103.49x = 12,287.77
  5. Step 5: Solve for x
    x = 12,287.77/103.49
  6. Step 6: Final answer
    x = 118.74

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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.