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Finding the Fourth Proportional to 86.65, 129.33 and 79.43

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Solution

The fourth proportional to 86.65, 129.33 and 79.43 is: 118.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.65 : 129.33 = 79.43 : x
  2. Step 2: Convert to fraction form
    86.65/129.33 = 79.43/x
  3. Step 3: Cross multiply
    86.65x = 129.33 × 79.43
  4. Step 4: Simplify right side
    86.65x = 10,272.68
  5. Step 5: Solve for x
    x = 10,272.68/86.65
  6. Step 6: Final answer
    x = 118.56

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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.