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Finding the Fourth Proportional to 89.81, 134.90 and 72.71

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Solution

The fourth proportional to 89.81, 134.90 and 72.71 is: 109.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.81 : 134.90 = 72.71 : x
  2. Step 2: Convert to fraction form
    89.81/134.90 = 72.71/x
  3. Step 3: Cross multiply
    89.81x = 134.90 × 72.71
  4. Step 4: Simplify right side
    89.81x = 9,808.58
  5. Step 5: Solve for x
    x = 9,808.58/89.81
  6. Step 6: Final answer
    x = 109.21

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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.