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Finding the Fourth Proportional to 77.85, 116.80 and 39.31

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Solution

The fourth proportional to 77.85, 116.80 and 39.31 is: 58.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.85 : 116.80 = 39.31 : x
  2. Step 2: Convert to fraction form
    77.85/116.80 = 39.31/x
  3. Step 3: Cross multiply
    77.85x = 116.80 × 39.31
  4. Step 4: Simplify right side
    77.85x = 4,591.41
  5. Step 5: Solve for x
    x = 4,591.41/77.85
  6. Step 6: Final answer
    x = 58.98

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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.