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Finding the Fourth Proportional to 131.20, 180.99 and 87.56

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Solution

The fourth proportional to 131.20, 180.99 and 87.56 is: 120.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    131.20 : 180.99 = 87.56 : x
  2. Step 2: Convert to fraction form
    131.20/180.99 = 87.56/x
  3. Step 3: Cross multiply
    131.20x = 180.99 × 87.56
  4. Step 4: Simplify right side
    131.20x = 15,847.48
  5. Step 5: Solve for x
    x = 15,847.48/131.20
  6. Step 6: Final answer
    x = 120.79

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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.