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Finding the Fourth Proportional to 109.38, 163.94 and 72.80

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Solution

The fourth proportional to 109.38, 163.94 and 72.80 is: 109.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    109.38 : 163.94 = 72.80 : x
  2. Step 2: Convert to fraction form
    109.38/163.94 = 72.80/x
  3. Step 3: Cross multiply
    109.38x = 163.94 × 72.80
  4. Step 4: Simplify right side
    109.38x = 11,933.65
  5. Step 5: Solve for x
    x = 11,933.65/109.38
  6. Step 6: Final answer
    x = 109.10

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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.