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Finding the Fourth Proportional to 310.91, 428.90 and 211.33

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Solution

The fourth proportional to 310.91, 428.90 and 211.33 is: 291.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    310.91 : 428.90 = 211.33 : x
  2. Step 2: Convert to fraction form
    310.91/428.90 = 211.33/x
  3. Step 3: Cross multiply
    310.91x = 428.90 × 211.33
  4. Step 4: Simplify right side
    310.91x = 90,640.12
  5. Step 5: Solve for x
    x = 90,640.12/310.91
  6. Step 6: Final answer
    x = 291.53

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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.