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Finding the Fourth Proportional to 86.66, 119.70 and 78.89

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Solution

The fourth proportional to 86.66, 119.70 and 78.89 is: 108.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.66 : 119.70 = 78.89 : x
  2. Step 2: Convert to fraction form
    86.66/119.70 = 78.89/x
  3. Step 3: Cross multiply
    86.66x = 119.70 × 78.89
  4. Step 4: Simplify right side
    86.66x = 9,442.74
  5. Step 5: Solve for x
    x = 9,442.74/86.66
  6. Step 6: Final answer
    x = 108.97

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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.