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Finding the Fourth Proportional to 120.77, 180.95 and 86.36

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Solution

The fourth proportional to 120.77, 180.95 and 86.36 is: 129.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.77 : 180.95 = 86.36 : x
  2. Step 2: Convert to fraction form
    120.77/180.95 = 86.36/x
  3. Step 3: Cross multiply
    120.77x = 180.95 × 86.36
  4. Step 4: Simplify right side
    120.77x = 15,626.84
  5. Step 5: Solve for x
    x = 15,626.84/120.77
  6. Step 6: Final answer
    x = 129.39

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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.