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Finding the Fourth Proportional to 137.90, 206.80 and 77.05

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Solution

The fourth proportional to 137.90, 206.80 and 77.05 is: 115.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.90 : 206.80 = 77.05 : x
  2. Step 2: Convert to fraction form
    137.90/206.80 = 77.05/x
  3. Step 3: Cross multiply
    137.90x = 206.80 × 77.05
  4. Step 4: Simplify right side
    137.90x = 15,934.44
  5. Step 5: Solve for x
    x = 15,934.44/137.90
  6. Step 6: Final answer
    x = 115.55

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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.