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Finding the Fourth Proportional to 421.87, 632.90 and 129.36

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Solution

The fourth proportional to 421.87, 632.90 and 129.36 is: 194.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.87 : 632.90 = 129.36 : x
  2. Step 2: Convert to fraction form
    421.87/632.90 = 129.36/x
  3. Step 3: Cross multiply
    421.87x = 632.90 × 129.36
  4. Step 4: Simplify right side
    421.87x = 81,871.94
  5. Step 5: Solve for x
    x = 81,871.94/421.87
  6. Step 6: Final answer
    x = 194.07

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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.