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Finding the Fourth Proportional to 256.88, 385.08 and 211.28

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Solution

The fourth proportional to 256.88, 385.08 and 211.28 is: 316.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.88 : 385.08 = 211.28 : x
  2. Step 2: Convert to fraction form
    256.88/385.08 = 211.28/x
  3. Step 3: Cross multiply
    256.88x = 385.08 × 211.28
  4. Step 4: Simplify right side
    256.88x = 81,359.70
  5. Step 5: Solve for x
    x = 81,359.70/256.88
  6. Step 6: Final answer
    x = 316.72

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.