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Finding the Fourth Proportional to 256.12, 384.21 and 82.80

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Solution

The fourth proportional to 256.12, 384.21 and 82.80 is: 124.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.12 : 384.21 = 82.80 : x
  2. Step 2: Convert to fraction form
    256.12/384.21 = 82.80/x
  3. Step 3: Cross multiply
    256.12x = 384.21 × 82.80
  4. Step 4: Simplify right side
    256.12x = 31,812.59
  5. Step 5: Solve for x
    x = 31,812.59/256.12
  6. Step 6: Final answer
    x = 124.21

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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.