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Finding the Fourth Proportional to 261.89, 361.78 and 209.78

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Solution

The fourth proportional to 261.89, 361.78 and 209.78 is: 289.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.89 : 361.78 = 209.78 : x
  2. Step 2: Convert to fraction form
    261.89/361.78 = 209.78/x
  3. Step 3: Cross multiply
    261.89x = 361.78 × 209.78
  4. Step 4: Simplify right side
    261.89x = 75,894.21
  5. Step 5: Solve for x
    x = 75,894.21/261.89
  6. Step 6: Final answer
    x = 289.79

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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.