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Finding the Fourth Proportional to 129.63, 178.85 and 80.49

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Solution

The fourth proportional to 129.63, 178.85 and 80.49 is: 111.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.63 : 178.85 = 80.49 : x
  2. Step 2: Convert to fraction form
    129.63/178.85 = 80.49/x
  3. Step 3: Cross multiply
    129.63x = 178.85 × 80.49
  4. Step 4: Simplify right side
    129.63x = 14,395.23
  5. Step 5: Solve for x
    x = 14,395.23/129.63
  6. Step 6: Final answer
    x = 111.05

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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.