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Finding the Fourth Proportional to 79.85, 120.00 and 39.30

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Solution

The fourth proportional to 79.85, 120.00 and 39.30 is: 59.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.85 : 120.00 = 39.30 : x
  2. Step 2: Convert to fraction form
    79.85/120.00 = 39.30/x
  3. Step 3: Cross multiply
    79.85x = 120.00 × 39.30
  4. Step 4: Simplify right side
    79.85x = 4,715.54
  5. Step 5: Solve for x
    x = 4,715.54/79.85
  6. Step 6: Final answer
    x = 59.06

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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.