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Finding the Fourth Proportional to 91.21, 136.76 and 55.21

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Solution

The fourth proportional to 91.21, 136.76 and 55.21 is: 82.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.21 : 136.76 = 55.21 : x
  2. Step 2: Convert to fraction form
    91.21/136.76 = 55.21/x
  3. Step 3: Cross multiply
    91.21x = 136.76 × 55.21
  4. Step 4: Simplify right side
    91.21x = 7,550.24
  5. Step 5: Solve for x
    x = 7,550.24/91.21
  6. Step 6: Final answer
    x = 82.78

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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.