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Finding the Fourth Proportional to 81.24, 112.21 and 61.67

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Solution

The fourth proportional to 81.24, 112.21 and 61.67 is: 85.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.24 : 112.21 = 61.67 : x
  2. Step 2: Convert to fraction form
    81.24/112.21 = 61.67/x
  3. Step 3: Cross multiply
    81.24x = 112.21 × 61.67
  4. Step 4: Simplify right side
    81.24x = 6,919.40
  5. Step 5: Solve for x
    x = 6,919.40/81.24
  6. Step 6: Final answer
    x = 85.17

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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.