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Finding the Fourth Proportional to 421.65, 632.56 and 129.19

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Solution

The fourth proportional to 421.65, 632.56 and 129.19 is: 193.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.65 : 632.56 = 129.19 : x
  2. Step 2: Convert to fraction form
    421.65/632.56 = 129.19/x
  3. Step 3: Cross multiply
    421.65x = 632.56 × 129.19
  4. Step 4: Simplify right side
    421.65x = 81,719.78
  5. Step 5: Solve for x
    x = 81,719.78/421.65
  6. Step 6: Final answer
    x = 193.81

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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.