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Finding the Fourth Proportional to 91.22, 136.78 and 47.81

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Solution

The fourth proportional to 91.22, 136.78 and 47.81 is: 71.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    91.22 : 136.78 = 47.81 : x
  2. Step 2: Convert to fraction form
    91.22/136.78 = 47.81/x
  3. Step 3: Cross multiply
    91.22x = 136.78 × 47.81
  4. Step 4: Simplify right side
    91.22x = 6,539.45
  5. Step 5: Solve for x
    x = 6,539.45/91.22
  6. Step 6: Final answer
    x = 71.69

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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.