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Finding the Fourth Proportional to 86.25, 129.93 and 79.92

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Solution

The fourth proportional to 86.25, 129.93 and 79.92 is: 120.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.25 : 129.93 = 79.92 : x
  2. Step 2: Convert to fraction form
    86.25/129.93 = 79.92/x
  3. Step 3: Cross multiply
    86.25x = 129.93 × 79.92
  4. Step 4: Simplify right side
    86.25x = 10,384.01
  5. Step 5: Solve for x
    x = 10,384.01/86.25
  6. Step 6: Final answer
    x = 120.39

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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.