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Finding the Fourth Proportional to 86.06, 128.81 and 79.65

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Solution

The fourth proportional to 86.06, 128.81 and 79.65 is: 119.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.06 : 128.81 = 79.65 : x
  2. Step 2: Convert to fraction form
    86.06/128.81 = 79.65/x
  3. Step 3: Cross multiply
    86.06x = 128.81 × 79.65
  4. Step 4: Simplify right side
    86.06x = 10,259.92
  5. Step 5: Solve for x
    x = 10,259.92/86.06
  6. Step 6: Final answer
    x = 119.21

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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.