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Finding the Fourth Proportional to 86.78, 130.38 and 72.44

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Solution

The fourth proportional to 86.78, 130.38 and 72.44 is: 108.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.78 : 130.38 = 72.44 : x
  2. Step 2: Convert to fraction form
    86.78/130.38 = 72.44/x
  3. Step 3: Cross multiply
    86.78x = 130.38 × 72.44
  4. Step 4: Simplify right side
    86.78x = 9,444.73
  5. Step 5: Solve for x
    x = 9,444.73/86.78
  6. Step 6: Final answer
    x = 108.84

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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.