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Finding the Fourth Proportional to 120.56, 180.79 and 87.86

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Solution

The fourth proportional to 120.56, 180.79 and 87.86 is: 131.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.56 : 180.79 = 87.86 : x
  2. Step 2: Convert to fraction form
    120.56/180.79 = 87.86/x
  3. Step 3: Cross multiply
    120.56x = 180.79 × 87.86
  4. Step 4: Simplify right side
    120.56x = 15,883.42
  5. Step 5: Solve for x
    x = 15,883.42/120.56
  6. Step 6: Final answer
    x = 131.75

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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.