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Finding the Fourth Proportional to 86.29, 129.44 and 21.29

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Solution

The fourth proportional to 86.29, 129.44 and 21.29 is: 31.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.29 : 129.44 = 21.29 : x
  2. Step 2: Convert to fraction form
    86.29/129.44 = 21.29/x
  3. Step 3: Cross multiply
    86.29x = 129.44 × 21.29
  4. Step 4: Simplify right side
    86.29x = 2,756.22
  5. Step 5: Solve for x
    x = 2,756.22/86.29
  6. Step 6: Final answer
    x = 31.94

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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.