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Finding the Fourth Proportional to 86.79, 119.78 and 57.66

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Solution

The fourth proportional to 86.79, 119.78 and 57.66 is: 79.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.79 : 119.78 = 57.66 : x
  2. Step 2: Convert to fraction form
    86.79/119.78 = 57.66/x
  3. Step 3: Cross multiply
    86.79x = 119.78 × 57.66
  4. Step 4: Simplify right side
    86.79x = 6,906.23
  5. Step 5: Solve for x
    x = 6,906.23/86.79
  6. Step 6: Final answer
    x = 79.57

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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.