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Finding the Fourth Proportional to 100.81, 151.20 and 81.44

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Solution

The fourth proportional to 100.81, 151.20 and 81.44 is: 122.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.81 : 151.20 = 81.44 : x
  2. Step 2: Convert to fraction form
    100.81/151.20 = 81.44/x
  3. Step 3: Cross multiply
    100.81x = 151.20 × 81.44
  4. Step 4: Simplify right side
    100.81x = 12,314.52
  5. Step 5: Solve for x
    x = 12,314.52/100.81
  6. Step 6: Final answer
    x = 122.16

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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.