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Finding the Fourth Proportional to 432.80, 644.85 and 421.19

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Solution

The fourth proportional to 432.80, 644.85 and 421.19 is: 627.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    432.80 : 644.85 = 421.19 : x
  2. Step 2: Convert to fraction form
    432.80/644.85 = 421.19/x
  3. Step 3: Cross multiply
    432.80x = 644.85 × 421.19
  4. Step 4: Simplify right side
    432.80x = 271,601.15
  5. Step 5: Solve for x
    x = 271,601.15/432.80
  6. Step 6: Final answer
    x = 627.55

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.