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Finding the Fourth Proportional to 256.72, 353.90 and 221.60

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Solution

The fourth proportional to 256.72, 353.90 and 221.60 is: 305.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.72 : 353.90 = 221.60 : x
  2. Step 2: Convert to fraction form
    256.72/353.90 = 221.60/x
  3. Step 3: Cross multiply
    256.72x = 353.90 × 221.60
  4. Step 4: Simplify right side
    256.72x = 78,424.24
  5. Step 5: Solve for x
    x = 78,424.24/256.72
  6. Step 6: Final answer
    x = 305.49

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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.