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Finding the Fourth Proportional to 79.78, 119.60 and 39.18

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Solution

The fourth proportional to 79.78, 119.60 and 39.18 is: 58.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.78 : 119.60 = 39.18 : x
  2. Step 2: Convert to fraction form
    79.78/119.60 = 39.18/x
  3. Step 3: Cross multiply
    79.78x = 119.60 × 39.18
  4. Step 4: Simplify right side
    79.78x = 4,685.93
  5. Step 5: Solve for x
    x = 4,685.93/79.78
  6. Step 6: Final answer
    x = 58.74

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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.