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Finding the Fourth Proportional to 86.21, 129.26 and 55.74

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Solution

The fourth proportional to 86.21, 129.26 and 55.74 is: 83.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.21 : 129.26 = 55.74 : x
  2. Step 2: Convert to fraction form
    86.21/129.26 = 55.74/x
  3. Step 3: Cross multiply
    86.21x = 129.26 × 55.74
  4. Step 4: Simplify right side
    86.21x = 7,204.67
  5. Step 5: Solve for x
    x = 7,204.67/86.21
  6. Step 6: Final answer
    x = 83.58

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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.