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Finding the Fourth Proportional to 129.67, 178.93 and 77.21

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Solution

The fourth proportional to 129.67, 178.93 and 77.21 is: 106.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.67 : 178.93 = 77.21 : x
  2. Step 2: Convert to fraction form
    129.67/178.93 = 77.21/x
  3. Step 3: Cross multiply
    129.67x = 178.93 × 77.21
  4. Step 4: Simplify right side
    129.67x = 13,815.19
  5. Step 5: Solve for x
    x = 13,815.19/129.67
  6. Step 6: Final answer
    x = 106.54

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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.