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Finding the Fourth Proportional to 137.80, 190.20 and 85.36

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Solution

The fourth proportional to 137.80, 190.20 and 85.36 is: 117.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    137.80 : 190.20 = 85.36 : x
  2. Step 2: Convert to fraction form
    137.80/190.20 = 85.36/x
  3. Step 3: Cross multiply
    137.80x = 190.20 × 85.36
  4. Step 4: Simplify right side
    137.80x = 16,235.47
  5. Step 5: Solve for x
    x = 16,235.47/137.80
  6. Step 6: Final answer
    x = 117.82

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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.