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Finding the Fourth Proportional to 387.78, 581.67 and 131.28

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Solution

The fourth proportional to 387.78, 581.67 and 131.28 is: 196.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    387.78 : 581.67 = 131.28 : x
  2. Step 2: Convert to fraction form
    387.78/581.67 = 131.28/x
  3. Step 3: Cross multiply
    387.78x = 581.67 × 131.28
  4. Step 4: Simplify right side
    387.78x = 76,361.64
  5. Step 5: Solve for x
    x = 76,361.64/387.78
  6. Step 6: Final answer
    x = 196.92

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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.