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Finding the Fourth Proportional to 312.38, 431.18 and 208.88

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Solution

The fourth proportional to 312.38, 431.18 and 208.88 is: 288.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.38 : 431.18 = 208.88 : x
  2. Step 2: Convert to fraction form
    312.38/431.18 = 208.88/x
  3. Step 3: Cross multiply
    312.38x = 431.18 × 208.88
  4. Step 4: Simplify right side
    312.38x = 90,061.68
  5. Step 5: Solve for x
    x = 90,061.68/312.38
  6. Step 6: Final answer
    x = 288.31

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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.