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Finding the Fourth Proportional to 86.87, 130.98 and 82.15

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Solution

The fourth proportional to 86.87, 130.98 and 82.15 is: 123.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.87 : 130.98 = 82.15 : x
  2. Step 2: Convert to fraction form
    86.87/130.98 = 82.15/x
  3. Step 3: Cross multiply
    86.87x = 130.98 × 82.15
  4. Step 4: Simplify right side
    86.87x = 10,759.99
  5. Step 5: Solve for x
    x = 10,759.99/86.87
  6. Step 6: Final answer
    x = 123.86

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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.