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Finding the Fourth Proportional to 109.02, 163.85 and 90.85

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Solution

The fourth proportional to 109.02, 163.85 and 90.85 is: 136.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    109.02 : 163.85 = 90.85 : x
  2. Step 2: Convert to fraction form
    109.02/163.85 = 90.85/x
  3. Step 3: Cross multiply
    109.02x = 163.85 × 90.85
  4. Step 4: Simplify right side
    109.02x = 14,885.77
  5. Step 5: Solve for x
    x = 14,885.77/109.02
  6. Step 6: Final answer
    x = 136.54

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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.