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Finding the Fourth Proportional to 256.69, 385.85 and 221.05

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Solution

The fourth proportional to 256.69, 385.85 and 221.05 is: 332.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.69 : 385.85 = 221.05 : x
  2. Step 2: Convert to fraction form
    256.69/385.85 = 221.05/x
  3. Step 3: Cross multiply
    256.69x = 385.85 × 221.05
  4. Step 4: Simplify right side
    256.69x = 85,292.14
  5. Step 5: Solve for x
    x = 85,292.14/256.69
  6. Step 6: Final answer
    x = 332.28

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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.