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Finding the Fourth Proportional to 256.96, 385.20 and 102.80

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Solution

The fourth proportional to 256.96, 385.20 and 102.80 is: 154.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.96 : 385.20 = 102.80 : x
  2. Step 2: Convert to fraction form
    256.96/385.20 = 102.80/x
  3. Step 3: Cross multiply
    256.96x = 385.20 × 102.80
  4. Step 4: Simplify right side
    256.96x = 39,598.56
  5. Step 5: Solve for x
    x = 39,598.56/256.96
  6. Step 6: Final answer
    x = 154.10

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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.