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Finding the Fourth Proportional to 256.65, 353.70 and 209.87

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Solution

The fourth proportional to 256.65, 353.70 and 209.87 is: 289.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    256.65 : 353.70 = 209.87 : x
  2. Step 2: Convert to fraction form
    256.65/353.70 = 209.87/x
  3. Step 3: Cross multiply
    256.65x = 353.70 × 209.87
  4. Step 4: Simplify right side
    256.65x = 74,229.25
  5. Step 5: Solve for x
    x = 74,229.25/256.65
  6. Step 6: Final answer
    x = 289.22

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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.