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Finding the Fourth Proportional to 129.21, 194.78 and 120.61

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Solution

The fourth proportional to 129.21, 194.78 and 120.61 is: 181.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.21 : 194.78 = 120.61 : x
  2. Step 2: Convert to fraction form
    129.21/194.78 = 120.61/x
  3. Step 3: Cross multiply
    129.21x = 194.78 × 120.61
  4. Step 4: Simplify right side
    129.21x = 23,492.60
  5. Step 5: Solve for x
    x = 23,492.60/129.21
  6. Step 6: Final answer
    x = 181.82

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.