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Finding the Fourth Proportional to 109.38, 163.72 and 89.90

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Solution

The fourth proportional to 109.38, 163.72 and 89.90 is: 134.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    109.38 : 163.72 = 89.90 : x
  2. Step 2: Convert to fraction form
    109.38/163.72 = 89.90/x
  3. Step 3: Cross multiply
    109.38x = 163.72 × 89.90
  4. Step 4: Simplify right side
    109.38x = 14,718.43
  5. Step 5: Solve for x
    x = 14,718.43/109.38
  6. Step 6: Final answer
    x = 134.56

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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.