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Finding the Fourth Proportional to 312.30, 431.17 and 202.05

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Solution

The fourth proportional to 312.30, 431.17 and 202.05 is: 278.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.30 : 431.17 = 202.05 : x
  2. Step 2: Convert to fraction form
    312.30/431.17 = 202.05/x
  3. Step 3: Cross multiply
    312.30x = 431.17 × 202.05
  4. Step 4: Simplify right side
    312.30x = 87,117.39
  5. Step 5: Solve for x
    x = 87,117.39/312.30
  6. Step 6: Final answer
    x = 278.95

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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.