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Finding the Fourth Proportional to 137.90, 206.99 and 86.65

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Solution

The fourth proportional to 137.90, 206.99 and 86.65 is: 130.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.90 : 206.99 = 86.65 : x
  2. Step 2: Convert to fraction form
    137.90/206.99 = 86.65/x
  3. Step 3: Cross multiply
    137.90x = 206.99 × 86.65
  4. Step 4: Simplify right side
    137.90x = 17,934.73
  5. Step 5: Solve for x
    x = 17,934.73/137.90
  6. Step 6: Final answer
    x = 130.05

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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.