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Finding the Fourth Proportional to 256.79, 385.21 and 83.46

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Solution

The fourth proportional to 256.79, 385.21 and 83.46 is: 125.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.79 : 385.21 = 83.46 : x
  2. Step 2: Convert to fraction form
    256.79/385.21 = 83.46/x
  3. Step 3: Cross multiply
    256.79x = 385.21 × 83.46
  4. Step 4: Simplify right side
    256.79x = 32,149.63
  5. Step 5: Solve for x
    x = 32,149.63/256.79
  6. Step 6: Final answer
    x = 125.20

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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.