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Finding the Fourth Proportional to 87.81, 131.76 and 51.72

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Solution

The fourth proportional to 87.81, 131.76 and 51.72 is: 77.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.81 : 131.76 = 51.72 : x
  2. Step 2: Convert to fraction form
    87.81/131.76 = 51.72/x
  3. Step 3: Cross multiply
    87.81x = 131.76 × 51.72
  4. Step 4: Simplify right side
    87.81x = 6,814.63
  5. Step 5: Solve for x
    x = 6,814.63/87.81
  6. Step 6: Final answer
    x = 77.61

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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.