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Finding the Fourth Proportional to 310.96, 428.78 and 212.56

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Solution

The fourth proportional to 310.96, 428.78 and 212.56 is: 293.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    310.96 : 428.78 = 212.56 : x
  2. Step 2: Convert to fraction form
    310.96/428.78 = 212.56/x
  3. Step 3: Cross multiply
    310.96x = 428.78 × 212.56
  4. Step 4: Simplify right side
    310.96x = 91,141.48
  5. Step 5: Solve for x
    x = 91,141.48/310.96
  6. Step 6: Final answer
    x = 293.10

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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.