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Finding the Fourth Proportional to 81.44, 111.93 and 72.18

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Solution

The fourth proportional to 81.44, 111.93 and 72.18 is: 99.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.44 : 111.93 = 72.18 : x
  2. Step 2: Convert to fraction form
    81.44/111.93 = 72.18/x
  3. Step 3: Cross multiply
    81.44x = 111.93 × 72.18
  4. Step 4: Simplify right side
    81.44x = 8,079.11
  5. Step 5: Solve for x
    x = 8,079.11/81.44
  6. Step 6: Final answer
    x = 99.21

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.