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Finding the Fourth Proportional to 256.71, 384.82 and 128.31

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Solution

The fourth proportional to 256.71, 384.82 and 128.31 is: 192.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.71 : 384.82 = 128.31 : x
  2. Step 2: Convert to fraction form
    256.71/384.82 = 128.31/x
  3. Step 3: Cross multiply
    256.71x = 384.82 × 128.31
  4. Step 4: Simplify right side
    256.71x = 49,376.25
  5. Step 5: Solve for x
    x = 49,376.25/256.71
  6. Step 6: Final answer
    x = 192.34

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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.