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Finding the Fourth Proportional to 85.14, 117.18 and 72.81

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Solution

The fourth proportional to 85.14, 117.18 and 72.81 is: 100.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.14 : 117.18 = 72.81 : x
  2. Step 2: Convert to fraction form
    85.14/117.18 = 72.81/x
  3. Step 3: Cross multiply
    85.14x = 117.18 × 72.81
  4. Step 4: Simplify right side
    85.14x = 8,531.88
  5. Step 5: Solve for x
    x = 8,531.88/85.14
  6. Step 6: Final answer
    x = 100.21

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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.