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Finding the Fourth Proportional to 256.51, 384.29 and 140.78

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Solution

The fourth proportional to 256.51, 384.29 and 140.78 is: 210.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.51 : 384.29 = 140.78 : x
  2. Step 2: Convert to fraction form
    256.51/384.29 = 140.78/x
  3. Step 3: Cross multiply
    256.51x = 384.29 × 140.78
  4. Step 4: Simplify right side
    256.51x = 54,100.60
  5. Step 5: Solve for x
    x = 54,100.60/256.51
  6. Step 6: Final answer
    x = 210.91

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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.