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Finding the Fourth Proportional to 103.61, 154.58 and 86.60

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Solution

The fourth proportional to 103.61, 154.58 and 86.60 is: 129.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.61 : 154.58 = 86.60 : x
  2. Step 2: Convert to fraction form
    103.61/154.58 = 86.60/x
  3. Step 3: Cross multiply
    103.61x = 154.58 × 86.60
  4. Step 4: Simplify right side
    103.61x = 13,386.58
  5. Step 5: Solve for x
    x = 13,386.58/103.61
  6. Step 6: Final answer
    x = 129.20

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.