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Finding the Fourth Proportional to 312.80, 431.78 and 194.80

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Solution

The fourth proportional to 312.80, 431.78 and 194.80 is: 268.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.80 : 431.78 = 194.80 : x
  2. Step 2: Convert to fraction form
    312.80/431.78 = 194.80/x
  3. Step 3: Cross multiply
    312.80x = 431.78 × 194.80
  4. Step 4: Simplify right side
    312.80x = 84,108.69
  5. Step 5: Solve for x
    x = 84,108.69/312.80
  6. Step 6: Final answer
    x = 268.89

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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.