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Finding the Fourth Proportional to 137.98, 206.74 and 86.64

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Solution

The fourth proportional to 137.98, 206.74 and 86.64 is: 129.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.98 : 206.74 = 86.64 : x
  2. Step 2: Convert to fraction form
    137.98/206.74 = 86.64/x
  3. Step 3: Cross multiply
    137.98x = 206.74 × 86.64
  4. Step 4: Simplify right side
    137.98x = 17,911.95
  5. Step 5: Solve for x
    x = 17,911.95/137.98
  6. Step 6: Final answer
    x = 129.82

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.