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Finding the Fourth Proportional to 86.95, 120.21 and 83.25

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Solution

The fourth proportional to 86.95, 120.21 and 83.25 is: 115.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.95 : 120.21 = 83.25 : x
  2. Step 2: Convert to fraction form
    86.95/120.21 = 83.25/x
  3. Step 3: Cross multiply
    86.95x = 120.21 × 83.25
  4. Step 4: Simplify right side
    86.95x = 10,007.17
  5. Step 5: Solve for x
    x = 10,007.17/86.95
  6. Step 6: Final answer
    x = 115.09

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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.