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Finding the Fourth Proportional to 207.09, 285.75 and 128.42

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Solution

The fourth proportional to 207.09, 285.75 and 128.42 is: 177.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    207.09 : 285.75 = 128.42 : x
  2. Step 2: Convert to fraction form
    207.09/285.75 = 128.42/x
  3. Step 3: Cross multiply
    207.09x = 285.75 × 128.42
  4. Step 4: Simplify right side
    207.09x = 36,694.59
  5. Step 5: Solve for x
    x = 36,694.59/207.09
  6. Step 6: Final answer
    x = 177.19

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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.