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Finding the Fourth Proportional to 137.90, 206.78 and 80.19

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Solution

The fourth proportional to 137.90, 206.78 and 80.19 is: 120.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.90 : 206.78 = 80.19 : x
  2. Step 2: Convert to fraction form
    137.90/206.78 = 80.19/x
  3. Step 3: Cross multiply
    137.90x = 206.78 × 80.19
  4. Step 4: Simplify right side
    137.90x = 16,581.29
  5. Step 5: Solve for x
    x = 16,581.29/137.90
  6. Step 6: Final answer
    x = 120.24

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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.