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Finding the Fourth Proportional to 120.76, 180.95 and 71.89

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Solution

The fourth proportional to 120.76, 180.95 and 71.89 is: 107.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.76 : 180.95 = 71.89 : x
  2. Step 2: Convert to fraction form
    120.76/180.95 = 71.89/x
  3. Step 3: Cross multiply
    120.76x = 180.95 × 71.89
  4. Step 4: Simplify right side
    120.76x = 13,007.68
  5. Step 5: Solve for x
    x = 13,007.68/120.76
  6. Step 6: Final answer
    x = 107.72

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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.