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Finding the Fourth Proportional to 137.80, 190.20 and 79.60

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Solution

The fourth proportional to 137.80, 190.20 and 79.60 is: 109.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.80 : 190.20 = 79.60 : x
  2. Step 2: Convert to fraction form
    137.80/190.20 = 79.60/x
  3. Step 3: Cross multiply
    137.80x = 190.20 × 79.60
  4. Step 4: Simplify right side
    137.80x = 15,139.92
  5. Step 5: Solve for x
    x = 15,139.92/137.80
  6. Step 6: Final answer
    x = 109.87

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.