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Finding the Fourth Proportional to 207.45, 286.15 and 128.79

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Solution

The fourth proportional to 207.45, 286.15 and 128.79 is: 177.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    207.45 : 286.15 = 128.79 : x
  2. Step 2: Convert to fraction form
    207.45/286.15 = 128.79/x
  3. Step 3: Cross multiply
    207.45x = 286.15 × 128.79
  4. Step 4: Simplify right side
    207.45x = 36,853.26
  5. Step 5: Solve for x
    x = 36,853.26/207.45
  6. Step 6: Final answer
    x = 177.65

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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.