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Finding the Fourth Proportional to 421.25, 631.87 and 147.31

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Solution

The fourth proportional to 421.25, 631.87 and 147.31 is: 220.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.25 : 631.87 = 147.31 : x
  2. Step 2: Convert to fraction form
    421.25/631.87 = 147.31/x
  3. Step 3: Cross multiply
    421.25x = 631.87 × 147.31
  4. Step 4: Simplify right side
    421.25x = 93,078.82
  5. Step 5: Solve for x
    x = 93,078.82/421.25
  6. Step 6: Final answer
    x = 220.96

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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.