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Finding the Fourth Proportional to 389.40, 537.20 and 256.45

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Solution

The fourth proportional to 389.40, 537.20 and 256.45 is: 353.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    389.40 : 537.20 = 256.45 : x
  2. Step 2: Convert to fraction form
    389.40/537.20 = 256.45/x
  3. Step 3: Cross multiply
    389.40x = 537.20 × 256.45
  4. Step 4: Simplify right side
    389.40x = 137,760.97
  5. Step 5: Solve for x
    x = 137,760.97/389.40
  6. Step 6: Final answer
    x = 353.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.