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Finding the Fourth Proportional to 256.57, 353.78 and 209.81

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Solution

The fourth proportional to 256.57, 353.78 and 209.81 is: 289.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.57 : 353.78 = 209.81 : x
  2. Step 2: Convert to fraction form
    256.57/353.78 = 209.81/x
  3. Step 3: Cross multiply
    256.57x = 353.78 × 209.81
  4. Step 4: Simplify right side
    256.57x = 74,226.39
  5. Step 5: Solve for x
    x = 74,226.39/256.57
  6. Step 6: Final answer
    x = 289.31

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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.