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Finding the Fourth Proportional to 120.30, 180.38 and 76.86

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Solution

The fourth proportional to 120.30, 180.38 and 76.86 is: 115.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.30 : 180.38 = 76.86 : x
  2. Step 2: Convert to fraction form
    120.30/180.38 = 76.86/x
  3. Step 3: Cross multiply
    120.30x = 180.38 × 76.86
  4. Step 4: Simplify right side
    120.30x = 13,864.01
  5. Step 5: Solve for x
    x = 13,864.01/120.30
  6. Step 6: Final answer
    x = 115.25

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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.