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Finding the Fourth Proportional to 120.54, 180.80 and 39.40

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Solution

The fourth proportional to 120.54, 180.80 and 39.40 is: 59.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    120.54 : 180.80 = 39.40 : x
  2. Step 2: Convert to fraction form
    120.54/180.80 = 39.40/x
  3. Step 3: Cross multiply
    120.54x = 180.80 × 39.40
  4. Step 4: Simplify right side
    120.54x = 7,123.52
  5. Step 5: Solve for x
    x = 7,123.52/120.54
  6. Step 6: Final answer
    x = 59.10

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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.