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Finding the Fourth Proportional to 421.71, 632.52 and 129.20

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Solution

The fourth proportional to 421.71, 632.52 and 129.20 is: 193.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.71 : 632.52 = 129.20 : x
  2. Step 2: Convert to fraction form
    421.71/632.52 = 129.20/x
  3. Step 3: Cross multiply
    421.71x = 632.52 × 129.20
  4. Step 4: Simplify right side
    421.71x = 81,718.42
  5. Step 5: Solve for x
    x = 81,718.42/421.71
  6. Step 6: Final answer
    x = 193.78

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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.