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Finding the Fourth Proportional to 86.49, 129.63 and 79.74

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Solution

The fourth proportional to 86.49, 129.63 and 79.74 is: 119.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.49 : 129.63 = 79.74 : x
  2. Step 2: Convert to fraction form
    86.49/129.63 = 79.74/x
  3. Step 3: Cross multiply
    86.49x = 129.63 × 79.74
  4. Step 4: Simplify right side
    86.49x = 10,336.70
  5. Step 5: Solve for x
    x = 10,336.70/86.49
  6. Step 6: Final answer
    x = 119.51

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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.