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Finding the Fourth Proportional to 86.21, 130.04 and 81.22

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Solution

The fourth proportional to 86.21, 130.04 and 81.22 is: 122.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.21 : 130.04 = 81.22 : x
  2. Step 2: Convert to fraction form
    86.21/130.04 = 81.22/x
  3. Step 3: Cross multiply
    86.21x = 130.04 × 81.22
  4. Step 4: Simplify right side
    86.21x = 10,561.85
  5. Step 5: Solve for x
    x = 10,561.85/86.21
  6. Step 6: Final answer
    x = 122.51

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.