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Finding the Fourth Proportional to 80.68, 120.40 and 72.60

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Solution

The fourth proportional to 80.68, 120.40 and 72.60 is: 108.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.68 : 120.40 = 72.60 : x
  2. Step 2: Convert to fraction form
    80.68/120.40 = 72.60/x
  3. Step 3: Cross multiply
    80.68x = 120.40 × 72.60
  4. Step 4: Simplify right side
    80.68x = 8,741.04
  5. Step 5: Solve for x
    x = 8,741.04/80.68
  6. Step 6: Final answer
    x = 108.34

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.