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Finding the Fourth Proportional to 276.78, 381.72 and 189.45

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Solution

The fourth proportional to 276.78, 381.72 and 189.45 is: 261.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    276.78 : 381.72 = 189.45 : x
  2. Step 2: Convert to fraction form
    276.78/381.72 = 189.45/x
  3. Step 3: Cross multiply
    276.78x = 381.72 × 189.45
  4. Step 4: Simplify right side
    276.78x = 72,316.85
  5. Step 5: Solve for x
    x = 72,316.85/276.78
  6. Step 6: Final answer
    x = 261.28

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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.