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Finding the Fourth Proportional to 80.90, 121.80 and 71.33

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Solution

The fourth proportional to 80.90, 121.80 and 71.33 is: 107.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.90 : 121.80 = 71.33 : x
  2. Step 2: Convert to fraction form
    80.90/121.80 = 71.33/x
  3. Step 3: Cross multiply
    80.90x = 121.80 × 71.33
  4. Step 4: Simplify right side
    80.90x = 8,688.11
  5. Step 5: Solve for x
    x = 8,688.11/80.90
  6. Step 6: Final answer
    x = 107.39

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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.