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Finding the Fourth Proportional to 79.90, 119.86 and 39.36

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Solution

The fourth proportional to 79.90, 119.86 and 39.36 is: 59.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.90 : 119.86 = 39.36 : x
  2. Step 2: Convert to fraction form
    79.90/119.86 = 39.36/x
  3. Step 3: Cross multiply
    79.90x = 119.86 × 39.36
  4. Step 4: Simplify right side
    79.90x = 4,717.69
  5. Step 5: Solve for x
    x = 4,717.69/79.90
  6. Step 6: Final answer
    x = 59.04

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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.