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Finding the Fourth Proportional to 120.19, 165.81 and 91.12

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Solution

The fourth proportional to 120.19, 165.81 and 91.12 is: 125.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.19 : 165.81 = 91.12 : x
  2. Step 2: Convert to fraction form
    120.19/165.81 = 91.12/x
  3. Step 3: Cross multiply
    120.19x = 165.81 × 91.12
  4. Step 4: Simplify right side
    120.19x = 15,108.61
  5. Step 5: Solve for x
    x = 15,108.61/120.19
  6. Step 6: Final answer
    x = 125.71

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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.