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Finding the Fourth Proportional to 86.22, 118.89 and 57.15

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Solution

The fourth proportional to 86.22, 118.89 and 57.15 is: 78.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.22 : 118.89 = 57.15 : x
  2. Step 2: Convert to fraction form
    86.22/118.89 = 57.15/x
  3. Step 3: Cross multiply
    86.22x = 118.89 × 57.15
  4. Step 4: Simplify right side
    86.22x = 6,794.56
  5. Step 5: Solve for x
    x = 6,794.56/86.22
  6. Step 6: Final answer
    x = 78.80

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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.