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Finding the Fourth Proportional to 312.75, 431.53 and 279.68

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Solution

The fourth proportional to 312.75, 431.53 and 279.68 is: 385.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.75 : 431.53 = 279.68 : x
  2. Step 2: Convert to fraction form
    312.75/431.53 = 279.68/x
  3. Step 3: Cross multiply
    312.75x = 431.53 × 279.68
  4. Step 4: Simplify right side
    312.75x = 120,687.45
  5. Step 5: Solve for x
    x = 120,687.45/312.75
  6. Step 6: Final answer
    x = 385.89

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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.