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Finding the Fourth Proportional to 129.72, 177.72 and 128.46

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Solution

The fourth proportional to 129.72, 177.72 and 128.46 is: 175.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.72 : 177.72 = 128.46 : x
  2. Step 2: Convert to fraction form
    129.72/177.72 = 128.46/x
  3. Step 3: Cross multiply
    129.72x = 177.72 × 128.46
  4. Step 4: Simplify right side
    129.72x = 22,829.91
  5. Step 5: Solve for x
    x = 22,829.91/129.72
  6. Step 6: Final answer
    x = 175.99

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.