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Finding the Fourth Proportional to 128.79, 176.45 and 123.93

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Solution

The fourth proportional to 128.79, 176.45 and 123.93 is: 169.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.79 : 176.45 = 123.93 : x
  2. Step 2: Convert to fraction form
    128.79/176.45 = 123.93/x
  3. Step 3: Cross multiply
    128.79x = 176.45 × 123.93
  4. Step 4: Simplify right side
    128.79x = 21,866.83
  5. Step 5: Solve for x
    x = 21,866.83/128.79
  6. Step 6: Final answer
    x = 169.79

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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.