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Finding the Fourth Proportional to 312.89, 431.91 and 215.15

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Solution

The fourth proportional to 312.89, 431.91 and 215.15 is: 296.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    312.89 : 431.91 = 215.15 : x
  2. Step 2: Convert to fraction form
    312.89/431.91 = 215.15/x
  3. Step 3: Cross multiply
    312.89x = 431.91 × 215.15
  4. Step 4: Simplify right side
    312.89x = 92,923.28
  5. Step 5: Solve for x
    x = 92,923.28/312.89
  6. Step 6: Final answer
    x = 296.99

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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.