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Finding the Fourth Proportional to 421.38, 631.95 and 161.20

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Solution

The fourth proportional to 421.38, 631.95 and 161.20 is: 241.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.38 : 631.95 = 161.20 : x
  2. Step 2: Convert to fraction form
    421.38/631.95 = 161.20/x
  3. Step 3: Cross multiply
    421.38x = 631.95 × 161.20
  4. Step 4: Simplify right side
    421.38x = 101,867.95
  5. Step 5: Solve for x
    x = 101,867.95/421.38
  6. Step 6: Final answer
    x = 241.75

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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.