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Finding the Fourth Proportional to 129.54, 178.77 and 72.77

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Solution

The fourth proportional to 129.54, 178.77 and 72.77 is: 100.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.54 : 178.77 = 72.77 : x
  2. Step 2: Convert to fraction form
    129.54/178.77 = 72.77/x
  3. Step 3: Cross multiply
    129.54x = 178.77 × 72.77
  4. Step 4: Simplify right side
    129.54x = 13,008.34
  5. Step 5: Solve for x
    x = 13,008.34/129.54
  6. Step 6: Final answer
    x = 100.42

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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.