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Finding the Fourth Proportional to 312.93, 431.78 and 207.90

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Solution

The fourth proportional to 312.93, 431.78 and 207.90 is: 286.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.93 : 431.78 = 207.90 : x
  2. Step 2: Convert to fraction form
    312.93/431.78 = 207.90/x
  3. Step 3: Cross multiply
    312.93x = 431.78 × 207.90
  4. Step 4: Simplify right side
    312.93x = 89,766.02
  5. Step 5: Solve for x
    x = 89,766.02/312.93
  6. Step 6: Final answer
    x = 286.86

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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.