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Finding the Fourth Proportional to 109.20, 150.60 and 78.10

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Solution

The fourth proportional to 109.20, 150.60 and 78.10 is: 107.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    109.20 : 150.60 = 78.10 : x
  2. Step 2: Convert to fraction form
    109.20/150.60 = 78.10/x
  3. Step 3: Cross multiply
    109.20x = 150.60 × 78.10
  4. Step 4: Simplify right side
    109.20x = 11,761.86
  5. Step 5: Solve for x
    x = 11,761.86/109.20
  6. Step 6: Final answer
    x = 107.71

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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.