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Finding the Fourth Proportional to 109.80, 164.72 and 81.28

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Solution

The fourth proportional to 109.80, 164.72 and 81.28 is: 121.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    109.80 : 164.72 = 81.28 : x
  2. Step 2: Convert to fraction form
    109.80/164.72 = 81.28/x
  3. Step 3: Cross multiply
    109.80x = 164.72 × 81.28
  4. Step 4: Simplify right side
    109.80x = 13,388.44
  5. Step 5: Solve for x
    x = 13,388.44/109.80
  6. Step 6: Final answer
    x = 121.93

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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.