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Finding the Fourth Proportional to 256.89, 384.78 and 213.45

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Solution

The fourth proportional to 256.89, 384.78 and 213.45 is: 319.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.89 : 384.78 = 213.45 : x
  2. Step 2: Convert to fraction form
    256.89/384.78 = 213.45/x
  3. Step 3: Cross multiply
    256.89x = 384.78 × 213.45
  4. Step 4: Simplify right side
    256.89x = 82,131.29
  5. Step 5: Solve for x
    x = 82,131.29/256.89
  6. Step 6: Final answer
    x = 319.71

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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.