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Finding the Fourth Proportional to 86.19, 128.32 and 85.27

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Solution

The fourth proportional to 86.19, 128.32 and 85.27 is: 126.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.19 : 128.32 = 85.27 : x
  2. Step 2: Convert to fraction form
    86.19/128.32 = 85.27/x
  3. Step 3: Cross multiply
    86.19x = 128.32 × 85.27
  4. Step 4: Simplify right side
    86.19x = 10,941.85
  5. Step 5: Solve for x
    x = 10,941.85/86.19
  6. Step 6: Final answer
    x = 126.95

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.