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Finding the Fourth Proportional to 256.80, 385.20 and 112.56

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Solution

The fourth proportional to 256.80, 385.20 and 112.56 is: 168.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.80 : 385.20 = 112.56 : x
  2. Step 2: Convert to fraction form
    256.80/385.20 = 112.56/x
  3. Step 3: Cross multiply
    256.80x = 385.20 × 112.56
  4. Step 4: Simplify right side
    256.80x = 43,358.11
  5. Step 5: Solve for x
    x = 43,358.11/256.80
  6. Step 6: Final answer
    x = 168.84

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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.