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Finding the Fourth Proportional to 421.45, 631.79 and 147.39

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Solution

The fourth proportional to 421.45, 631.79 and 147.39 is: 220.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.45 : 631.79 = 147.39 : x
  2. Step 2: Convert to fraction form
    421.45/631.79 = 147.39/x
  3. Step 3: Cross multiply
    421.45x = 631.79 × 147.39
  4. Step 4: Simplify right side
    421.45x = 93,119.10
  5. Step 5: Solve for x
    x = 93,119.10/421.45
  6. Step 6: Final answer
    x = 220.95

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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.