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Finding the Fourth Proportional to 212.81, 319.32 and 91.11

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Solution

The fourth proportional to 212.81, 319.32 and 91.11 is: 136.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.81 : 319.32 = 91.11 : x
  2. Step 2: Convert to fraction form
    212.81/319.32 = 91.11/x
  3. Step 3: Cross multiply
    212.81x = 319.32 × 91.11
  4. Step 4: Simplify right side
    212.81x = 29,093.25
  5. Step 5: Solve for x
    x = 29,093.25/212.81
  6. Step 6: Final answer
    x = 136.71

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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.