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Finding the Fourth Proportional to 256.38, 384.63 and 128.13

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Solution

The fourth proportional to 256.38, 384.63 and 128.13 is: 192.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.38 : 384.63 = 128.13 : x
  2. Step 2: Convert to fraction form
    256.38/384.63 = 128.13/x
  3. Step 3: Cross multiply
    256.38x = 384.63 × 128.13
  4. Step 4: Simplify right side
    256.38x = 49,282.64
  5. Step 5: Solve for x
    x = 49,282.64/256.38
  6. Step 6: Final answer
    x = 192.22

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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.