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Finding the Fourth Proportional to 109.28, 150.80 and 81.68

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Solution

The fourth proportional to 109.28, 150.80 and 81.68 is: 112.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    109.28 : 150.80 = 81.68 : x
  2. Step 2: Convert to fraction form
    109.28/150.80 = 81.68/x
  3. Step 3: Cross multiply
    109.28x = 150.80 × 81.68
  4. Step 4: Simplify right side
    109.28x = 12,316.18
  5. Step 5: Solve for x
    x = 12,316.18/109.28
  6. Step 6: Final answer
    x = 112.70

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.