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Finding the Fourth Proportional to 261.28, 391.78 and 122.43

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Solution

The fourth proportional to 261.28, 391.78 and 122.43 is: 183.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    261.28 : 391.78 = 122.43 : x
  2. Step 2: Convert to fraction form
    261.28/391.78 = 122.43/x
  3. Step 3: Cross multiply
    261.28x = 391.78 × 122.43
  4. Step 4: Simplify right side
    261.28x = 47,965.63
  5. Step 5: Solve for x
    x = 47,965.63/261.28
  6. Step 6: Final answer
    x = 183.58

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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.