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Finding the Fourth Proportional to 129.70, 177.77 and 128.80

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Solution

The fourth proportional to 129.70, 177.77 and 128.80 is: 176.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.70 : 177.77 = 128.80 : x
  2. Step 2: Convert to fraction form
    129.70/177.77 = 128.80/x
  3. Step 3: Cross multiply
    129.70x = 177.77 × 128.80
  4. Step 4: Simplify right side
    129.70x = 22,896.78
  5. Step 5: Solve for x
    x = 22,896.78/129.70
  6. Step 6: Final answer
    x = 176.54

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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.