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Finding the Fourth Proportional to 256.63, 385.01 and 128.38

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Solution

The fourth proportional to 256.63, 385.01 and 128.38 is: 192.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.63 : 385.01 = 128.38 : x
  2. Step 2: Convert to fraction form
    256.63/385.01 = 128.38/x
  3. Step 3: Cross multiply
    256.63x = 385.01 × 128.38
  4. Step 4: Simplify right side
    256.63x = 49,425.02
  5. Step 5: Solve for x
    x = 49,425.02/256.63
  6. Step 6: Final answer
    x = 192.60

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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.