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Finding the Fourth Proportional to 128.27, 177.15 and 123.72

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Solution

The fourth proportional to 128.27, 177.15 and 123.72 is: 170.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.27 : 177.15 = 123.72 : x
  2. Step 2: Convert to fraction form
    128.27/177.15 = 123.72/x
  3. Step 3: Cross multiply
    128.27x = 177.15 × 123.72
  4. Step 4: Simplify right side
    128.27x = 21,916.11
  5. Step 5: Solve for x
    x = 21,916.11/128.27
  6. Step 6: Final answer
    x = 170.86

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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.