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Finding the Fourth Proportional to 426.31, 639.47 and 118.20

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Solution

The fourth proportional to 426.31, 639.47 and 118.20 is: 177.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.31 : 639.47 = 118.20 : x
  2. Step 2: Convert to fraction form
    426.31/639.47 = 118.20/x
  3. Step 3: Cross multiply
    426.31x = 639.47 × 118.20
  4. Step 4: Simplify right side
    426.31x = 75,585.35
  5. Step 5: Solve for x
    x = 75,585.35/426.31
  6. Step 6: Final answer
    x = 177.30

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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.