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Finding the Fourth Proportional to 92.80, 139.47 and 86.11

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Solution

The fourth proportional to 92.80, 139.47 and 86.11 is: 129.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    92.80 : 139.47 = 86.11 : x
  2. Step 2: Convert to fraction form
    92.80/139.47 = 86.11/x
  3. Step 3: Cross multiply
    92.80x = 139.47 × 86.11
  4. Step 4: Simplify right side
    92.80x = 12,009.76
  5. Step 5: Solve for x
    x = 12,009.76/92.80
  6. Step 6: Final answer
    x = 129.42

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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.