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Finding the Fourth Proportional to 207.58, 286.40 and 128.91

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Solution

The fourth proportional to 207.58, 286.40 and 128.91 is: 177.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    207.58 : 286.40 = 128.91 : x
  2. Step 2: Convert to fraction form
    207.58/286.40 = 128.91/x
  3. Step 3: Cross multiply
    207.58x = 286.40 × 128.91
  4. Step 4: Simplify right side
    207.58x = 36,919.61
  5. Step 5: Solve for x
    x = 36,919.61/207.58
  6. Step 6: Final answer
    x = 177.86

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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.