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Finding the Fourth Proportional to 77.89, 116.86 and 39.40

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Solution

The fourth proportional to 77.89, 116.86 and 39.40 is: 59.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.89 : 116.86 = 39.40 : x
  2. Step 2: Convert to fraction form
    77.89/116.86 = 39.40/x
  3. Step 3: Cross multiply
    77.89x = 116.86 × 39.40
  4. Step 4: Simplify right side
    77.89x = 4,604.28
  5. Step 5: Solve for x
    x = 4,604.28/77.89
  6. Step 6: Final answer
    x = 59.11

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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.