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Finding the Fourth Proportional to 78.76, 118.09 and 39.71

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Solution

The fourth proportional to 78.76, 118.09 and 39.71 is: 59.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    78.76 : 118.09 = 39.71 : x
  2. Step 2: Convert to fraction form
    78.76/118.09 = 39.71/x
  3. Step 3: Cross multiply
    78.76x = 118.09 × 39.71
  4. Step 4: Simplify right side
    78.76x = 4,689.35
  5. Step 5: Solve for x
    x = 4,689.35/78.76
  6. Step 6: Final answer
    x = 59.54

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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.