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Finding the Fourth Proportional to 81.16, 110.50 and 79.72

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Solution

The fourth proportional to 81.16, 110.50 and 79.72 is: 108.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.16 : 110.50 = 79.72 : x
  2. Step 2: Convert to fraction form
    81.16/110.50 = 79.72/x
  3. Step 3: Cross multiply
    81.16x = 110.50 × 79.72
  4. Step 4: Simplify right side
    81.16x = 8,809.06
  5. Step 5: Solve for x
    x = 8,809.06/81.16
  6. Step 6: Final answer
    x = 108.54

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Why These Related Problems?

These problems maintain the same ratio (1.36) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.