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Finding the Fourth Proportional to 138.04, 206.80 and 80.20

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Solution

The fourth proportional to 138.04, 206.80 and 80.20 is: 120.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.04 : 206.80 = 80.20 : x
  2. Step 2: Convert to fraction form
    138.04/206.80 = 80.20/x
  3. Step 3: Cross multiply
    138.04x = 206.80 × 80.20
  4. Step 4: Simplify right side
    138.04x = 16,585.36
  5. Step 5: Solve for x
    x = 16,585.36/138.04
  6. Step 6: Final answer
    x = 120.15

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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.