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Finding the Fourth Proportional to 312.64, 431.56 and 279.83

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Solution

The fourth proportional to 312.64, 431.56 and 279.83 is: 386.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.64 : 431.56 = 279.83 : x
  2. Step 2: Convert to fraction form
    312.64/431.56 = 279.83/x
  3. Step 3: Cross multiply
    312.64x = 431.56 × 279.83
  4. Step 4: Simplify right side
    312.64x = 120,765.21
  5. Step 5: Solve for x
    x = 120,765.21/312.64
  6. Step 6: Final answer
    x = 386.28

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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.