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Finding the Fourth Proportional to 87.81, 131.72 and 47.28

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Solution

The fourth proportional to 87.81, 131.72 and 47.28 is: 70.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.81 : 131.72 = 47.28 : x
  2. Step 2: Convert to fraction form
    87.81/131.72 = 47.28/x
  3. Step 3: Cross multiply
    87.81x = 131.72 × 47.28
  4. Step 4: Simplify right side
    87.81x = 6,227.72
  5. Step 5: Solve for x
    x = 6,227.72/87.81
  6. Step 6: Final answer
    x = 70.92

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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.